Reduce MCP token usage

This commit is contained in:
2026-05-29 13:16:05 +01:00
parent da46340a82
commit 51aac9f447
9 changed files with 453 additions and 137 deletions

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@@ -16,6 +16,10 @@ loosely follows [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
- Grid-mode `get_process_output` now returns whitespace-normalized
text to avoid sending padded terminal rows and repeated blank lines
over MCP.
- MCP responses now use slimmer defaults: tool-call JSON is no longer
duplicated into text content, large output and scratchpad reads are
capped with truncation metadata, and `whoami` / `get_project_status`
only include full tool lists when `include_tools` is requested.
### Fixed
- Injected agent input now sends the submit Enter as a separated,

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@@ -532,6 +532,12 @@ func (c *Child) StreamRead(since int64) ([]byte, int64) {
return out, end
}
func (c *Child) StreamOffset() int64 {
c.ringMu.Lock()
defer c.ringMu.Unlock()
return c.ringWrites
}
func (c *Child) signal(sig syscall.Signal) error {
pty := c.PTY()
if pty == nil {

View File

@@ -65,6 +65,15 @@ type toolHost struct {
timers *timerManager
}
const (
defaultMCPContentBytes = 12_000
maxMCPContentBytes = 65_536
defaultMCPTailBytes = 8_000
defaultScratchpadReadBytes = 12_000
defaultSearchLineBytes = 2_000
maxSearchMatches = 50
)
func newToolHost(sess *Session, pads *scratchpad.Store, launcher *Launcher, presets preset.Set, tr *trust.Store, cols, rows uint16) *toolHost {
h := &toolHost{
sess: sess,
@@ -353,8 +362,8 @@ func (h *toolHost) GetProcessStatus(callerID, processID string) (mcp.ProcessStat
return st, nil
}
func (h *toolHost) GetProjectStatus(callerID string) (mcp.ProjectStatus, error) {
caller := h.WhoAmI(callerID)
func (h *toolHost) GetProjectStatus(callerID string, includeTools bool) (mcp.ProjectStatus, error) {
caller := h.WhoAmI(callerID, includeTools)
processes := h.ListProcesses(callerID, "")
pads, _ := h.pads.List()
return mcp.ProjectStatus{
@@ -365,7 +374,8 @@ func (h *toolHost) GetProjectStatus(callerID string) (mcp.ProjectStatus, error)
}, nil
}
func (h *toolHost) GetProcessOutput(callerID, processID, mode string, sinceOffset int64) (mcp.ProcessOutput, error) {
func (h *toolHost) GetProcessOutput(callerID string, args mcp.ProcessOutputArgs) (mcp.ProcessOutput, error) {
processID, mode, sinceOffset := args.ProcessID, args.Mode, args.SinceOffset
c := h.sess.FindChild(processID)
if c == nil {
return mcp.ProcessOutput{}, mcp.Errorf(mcp.ErrorKindNotFound, "no such process %q", processID)
@@ -399,11 +409,12 @@ func (h *toolHost) GetProcessOutput(callerID, processID, mode string, sinceOffse
if c.Kind == KindAgent {
txt = applyChromeTrim(txt, h.chromeHintsFor(c.PresetRef))
}
out.Content = normalizeGridText(txt)
content := normalizeGridText(txt)
out.Content, out.ContentBytes, out.Truncated, out.TruncatedBytes = capTextMiddle(content, capLimit(args.MaxBytes, defaultMCPContentBytes))
return out, nil
case "stream":
b, end := c.StreamRead(sinceOffset)
out.Content = string(stripANSIBytes(nil, b))
out.Content, out.ContentBytes, out.Truncated, out.TruncatedBytes = capBytesTail(stripANSIBytes(nil, b), capLimit(args.MaxBytes, defaultMCPContentBytes))
out.NewOffset = end
return out, nil
default:
@@ -411,34 +422,46 @@ func (h *toolHost) GetProcessOutput(callerID, processID, mode string, sinceOffse
}
}
func (h *toolHost) GetProcessRawOutput(callerID, processID string, sinceOffset int64) (mcp.RawOutput, error) {
c := h.sess.FindChild(processID)
func (h *toolHost) GetProcessRawOutput(callerID string, args mcp.RawOutputArgs) (mcp.RawOutput, error) {
c := h.sess.FindChild(args.ProcessID)
if c == nil {
return mcp.RawOutput{}, mcp.Errorf(mcp.ErrorKindNotFound, "no such process %q", processID)
return mcp.RawOutput{}, mcp.Errorf(mcp.ErrorKindNotFound, "no such process %q", args.ProcessID)
}
b, end := c.StreamRead(sinceOffset)
b, end := c.StreamRead(args.SinceOffset)
content, contentBytes, truncated, truncatedBytes := capBytesTail(b, capLimit(args.MaxBytes, defaultMCPContentBytes))
return mcp.RawOutput{
Content: string(b),
NewOffset: end,
Status: string(c.Status()),
Content: content,
NewOffset: end,
Status: string(c.Status()),
ContentBytes: contentBytes,
Truncated: truncated,
TruncatedBytes: truncatedBytes,
}, nil
}
func (h *toolHost) SearchOutput(callerID, processID, pattern, kind string, limit int) (mcp.SearchResult, error) {
c := h.sess.FindChild(processID)
func (h *toolHost) SearchOutput(callerID string, args mcp.SearchOutputArgs) (mcp.SearchResult, error) {
c := h.sess.FindChild(args.ProcessID)
if c == nil {
return mcp.SearchResult{}, mcp.Errorf(mcp.ErrorKindNotFound, "no such process %q", processID)
return mcp.SearchResult{}, mcp.Errorf(mcp.ErrorKindNotFound, "no such process %q", args.ProcessID)
}
re, err := regexp.Compile(pattern)
re, err := regexp.Compile(args.Pattern)
if err != nil {
return mcp.SearchResult{}, mcp.Errorf(mcp.ErrorKindInvalidArgs, "regex: %v", err)
}
b, _ := c.StreamRead(0)
if kind == "rendered" {
if args.Kind == "rendered" {
b = stripANSIBytes(nil, b)
}
text := string(b)
lines := strings.Split(text, "\n")
limit := args.Limit
if limit <= 0 {
limit = 10
}
if limit > maxSearchMatches {
limit = maxSearchMatches
}
lineLimit := capLimit(args.MaxBytes, defaultSearchLineBytes)
matches := make([]mcp.SearchMatch, 0, limit)
truncated := false
for i, line := range lines {
@@ -447,6 +470,8 @@ func (h *toolHost) SearchOutput(callerID, processID, pattern, kind string, limit
truncated = true
break
}
line, _, lineTruncated, _ := capTextTail(line, lineLimit)
truncated = truncated || lineTruncated
matches = append(matches, mcp.SearchMatch{LineNo: i + 1, Text: line})
}
}
@@ -588,6 +613,7 @@ func (h *toolHost) SendInput(callerID string, args mcp.SendInputArgs) (mcp.SendI
if err != nil {
return mcp.SendInputResult{}, err
}
tailSince := c.StreamOffset()
if err := c.InjectAsOrchestrator(payload); err != nil {
return mcp.SendInputResult{}, err
}
@@ -599,7 +625,12 @@ func (h *toolHost) SendInput(callerID string, args mcp.SendInputArgs) (mcp.SendI
}
if mode != "none" {
time.Sleep(time.Duration(args.WaitMS) * time.Millisecond)
tail, err := h.GetProcessOutput(callerID, args.ProcessID, mode, 0)
tail, err := h.GetProcessOutput(callerID, mcp.ProcessOutputArgs{
ProcessID: args.ProcessID,
Mode: mode,
SinceOffset: tailSince,
MaxBytes: capLimit(args.TailMaxBytes, defaultMCPTailBytes),
})
if err == nil {
res.Tail = &tail
}
@@ -813,8 +844,30 @@ func (h *toolHost) TimerList(callerID string) ([]mcp.TimerInfo, error) {
func (h *toolHost) ScratchpadList() ([]scratchpad.Entry, error) { return h.pads.List() }
func (h *toolHost) ScratchpadRead(name string) (string, string, error) {
return h.pads.Read(name)
func (h *toolHost) ScratchpadRead(args mcp.ScratchpadReadArgs) (mcp.ScratchpadReadResult, error) {
content, rev, err := h.pads.Read(args.Name)
if err != nil {
return mcp.ScratchpadReadResult{}, err
}
offset := args.Offset
if offset < 0 {
offset = 0
}
if offset > len(content) {
offset = len(content)
}
limited, contentBytes, truncated, truncatedBytes := capTextHead(content[offset:], capLimit(args.MaxBytes, defaultScratchpadReadBytes))
next := offset + contentBytes
return mcp.ScratchpadReadResult{
Content: limited,
Revision: rev,
Offset: offset,
NextOffset: next,
ContentBytes: contentBytes,
TotalBytes: len(content),
Truncated: truncated,
TruncatedBytes: truncatedBytes,
}, nil
}
func (h *toolHost) ScratchpadWrite(name, content, expectedRevision string) (string, error) {
@@ -841,7 +894,7 @@ func (h *toolHost) ScratchpadDelete(name string) error {
return err
}
func (h *toolHost) WhoAmI(callerID string) mcp.WhoAmI {
func (h *toolHost) WhoAmI(callerID string, includeTools bool) mcp.WhoAmI {
w := mcp.WhoAmI{
ProcessID: callerID,
Role: h.CallerRole(callerID),
@@ -849,7 +902,9 @@ func (h *toolHost) WhoAmI(callerID string) mcp.WhoAmI {
Path: h.sess.projectDir,
Key: h.sess.projectKey,
},
AvailableTools: availableToolsForRole(h.CallerRole(callerID)),
}
if includeTools {
w.AvailableTools = availableToolsForRole(h.CallerRole(callerID))
}
if c := h.sess.FindChild(callerID); c != nil {
w.Name = c.DisplayName()
@@ -1043,6 +1098,51 @@ func normalizeGridText(s string) string {
return strings.Join(out, "\n")
}
func capLimit(requested, def int) int {
if requested <= 0 {
requested = def
}
if requested > maxMCPContentBytes {
requested = maxMCPContentBytes
}
if requested < 0 {
return 0
}
return requested
}
func capBytesTail(b []byte, limit int) (string, int, bool, int) {
if limit <= 0 || len(b) <= limit {
return string(b), len(b), false, 0
}
dropped := len(b) - limit
return string(b[dropped:]), limit, true, dropped
}
func capTextTail(s string, limit int) (string, int, bool, int) {
return capBytesTail([]byte(s), limit)
}
func capTextHead(s string, limit int) (string, int, bool, int) {
if limit <= 0 || len(s) <= limit {
return s, len(s), false, 0
}
return s[:limit], limit, true, len(s) - limit
}
func capTextMiddle(s string, limit int) (string, int, bool, int) {
if limit <= 0 || len(s) <= limit {
return s, len(s), false, 0
}
const marker = "\n...[truncated]...\n"
if limit <= len(marker)+2 {
return s[len(s)-limit:], limit, true, len(s) - limit
}
head := (limit - len(marker)) / 2
tail := limit - len(marker) - head
return s[:head] + marker + s[len(s)-tail:], limit, true, len(s) - limit
}
// stripANSIBytes is the byte-slice form of stripANSI. Skips the
// string conversion and the regex DFA — useful when the caller will
// itself walk the result line-by-line (SearchOutput) or feed it to a

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@@ -5,6 +5,7 @@ import (
"testing"
"github.com/hjbdev/patterm/internal/mcp"
"github.com/hjbdev/patterm/internal/scratchpad"
)
// mkChild builds a Child without starting a PTY. Use sparingly — the
@@ -134,6 +135,42 @@ func TestWrapSubAgentPromptEmptyStaysEmpty(t *testing.T) {
}
}
func TestMCPContentCapsPreferRecentStreamBytes(t *testing.T) {
got, gotBytes, truncated, dropped := capBytesTail([]byte("abcdefghijklmnop"), 6)
if got != "klmnop" || gotBytes != 6 || !truncated || dropped != 10 {
t.Fatalf("capBytesTail = (%q, %d, %v, %d)", got, gotBytes, truncated, dropped)
}
}
func TestMCPGridCapKeepsHeadAndTail(t *testing.T) {
got, gotBytes, truncated, dropped := capTextMiddle("abcdefghijklmnopqrstuvwxyz", 24)
if gotBytes != 24 || !truncated || dropped != 2 {
t.Fatalf("capTextMiddle metadata = (%d, %v, %d), content %q", gotBytes, truncated, dropped, got)
}
if !strings.Contains(got, "...[truncated]...") {
t.Fatalf("capTextMiddle missing marker: %q", got)
}
}
func TestScratchpadReadPagesLargeContent(t *testing.T) {
t.Setenv("XDG_DATA_HOME", t.TempDir())
store, err := scratchpad.Open("test-project")
if err != nil {
t.Fatalf("scratchpad open: %v", err)
}
if _, err := store.Write("notes.md", "abcdefghijklmnopqrstuvwxyz", ""); err != nil {
t.Fatalf("scratchpad write: %v", err)
}
h := &toolHost{pads: store}
res, err := h.ScratchpadRead(mcp.ScratchpadReadArgs{Name: "notes.md", Offset: 5, MaxBytes: 7})
if err != nil {
t.Fatalf("ScratchpadRead: %v", err)
}
if res.Content != "fghijkl" || !res.Truncated || res.NextOffset != 12 || res.TotalBytes != 26 {
t.Fatalf("ScratchpadRead result = %+v", res)
}
}
func TestHelpLifecycleTopicCoversCleanup(t *testing.T) {
resp := helpFor("lifecycle")
if resp.Topic != "lifecycle" {

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@@ -561,14 +561,16 @@ func (m *timerManager) TimerList(ownerID string) []mcp.TimerInfo {
if t.status != timerStatusPending && t.status != timerStatusPaused {
continue
}
body, bodyTruncated := timerBodyPreview(t.body)
info := mcp.TimerInfo{
ID: t.id,
Label: t.label,
Body: t.body,
Kind: string(t.kind),
Status: t.status,
OwnerID: t.ownerID,
WatchedIDs: append([]string(nil), t.watched...),
ID: t.id,
Label: t.label,
Body: body,
BodyTruncated: bodyTruncated,
Kind: string(t.kind),
Status: t.status,
OwnerID: t.ownerID,
WatchedIDs: append([]string(nil), t.watched...),
}
if t.status == timerStatusPending && !t.firesAt.IsZero() {
info.FiresAtUnixMS = t.firesAt.UnixMilli()
@@ -581,6 +583,14 @@ func (m *timerManager) TimerList(ownerID string) []mcp.TimerInfo {
return out
}
func timerBodyPreview(body string) (string, bool) {
const max = 500
if len(body) <= max {
return body, false
}
return body[:max], true
}
// activeForChild returns the nearest pending or paused timer attached
// to child id (either owned by it or watching it). Used by the sidebar
// for the "⏱ 12s" indicator. nil when none.

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@@ -134,16 +134,16 @@ func (h *blockingToolHost) ListProcesses(string, string) []ProcessInfo { return
func (h *blockingToolHost) GetProcessStatus(string, string) (ProcessStatus, error) {
return ProcessStatus{ProcessInfo: ProcessInfo{ID: "p_fast", Status: "running"}}, nil
}
func (h *blockingToolHost) GetProjectStatus(string) (ProjectStatus, error) {
func (h *blockingToolHost) GetProjectStatus(string, bool) (ProjectStatus, error) {
return ProjectStatus{}, nil
}
func (h *blockingToolHost) GetProcessOutput(string, string, string, int64) (ProcessOutput, error) {
func (h *blockingToolHost) GetProcessOutput(string, ProcessOutputArgs) (ProcessOutput, error) {
return ProcessOutput{}, nil
}
func (h *blockingToolHost) GetProcessRawOutput(string, string, int64) (RawOutput, error) {
func (h *blockingToolHost) GetProcessRawOutput(string, RawOutputArgs) (RawOutput, error) {
return RawOutput{}, nil
}
func (h *blockingToolHost) SearchOutput(string, string, string, string, int) (SearchResult, error) {
func (h *blockingToolHost) SearchOutput(string, SearchOutputArgs) (SearchResult, error) {
return SearchResult{}, nil
}
func (h *blockingToolHost) WaitForPattern(string, string, string, float64, string) (bool, string, error) {
@@ -178,13 +178,13 @@ func (h *blockingToolHost) TimerList(string) ([]TimerInfo, error) {
return nil, nil
}
func (h *blockingToolHost) ScratchpadList() ([]scratchpad.Entry, error) { return nil, nil }
func (h *blockingToolHost) ScratchpadRead(string) (string, string, error) {
return "", "", nil
func (h *blockingToolHost) ScratchpadRead(ScratchpadReadArgs) (ScratchpadReadResult, error) {
return ScratchpadReadResult{}, nil
}
func (h *blockingToolHost) ScratchpadWrite(string, string, string) (string, error) {
return "", nil
}
func (h *blockingToolHost) ScratchpadAppend(string, string) error { return nil }
func (h *blockingToolHost) ScratchpadDelete(string) error { return nil }
func (h *blockingToolHost) WhoAmI(string) WhoAmI { return WhoAmI{} }
func (h *blockingToolHost) WhoAmI(string, bool) WhoAmI { return WhoAmI{} }
func (h *blockingToolHost) Help(string, string) HelpResponse { return HelpResponse{} }

View File

@@ -3,6 +3,8 @@ package mcp
import (
"encoding/json"
"fmt"
"github.com/hjbdev/patterm/internal/scratchpad"
)
// MCP protocol surface. The patterm server originally exposed each
@@ -43,7 +45,7 @@ var serverInfo = map[string]any{
// up as sub-agents and won't be tied into the patterm lifecycle.
//
// Keep this short — clients vary in how much they surface to the LLM.
const serverInstructions = "You are already running INSIDE patterm; the `patterm` MCP server is connected over the same stdio MCP transport you use for any other MCP server. Use the MCP tools you see in tools/list — do NOT (a) try to launch `patterm` or `patterm mcp-stdio` yourself, (b) poke the Unix socket through perl / nc / socat / curl, or (c) shell out to `claude` / `codex` / `opencode` to start a peer. Any of those bypasses caller-identity and the new agent will land as a stray top-level tab instead of a child under you. Start with `whoami` for your role and the full tool list, then `help('topics')` for orientation. `spawn_agent` is the only correct way to start a sub-agent; `spawn_process` is for non-LLM commands; `list_processes` / `get_process_output` inspect them; `send_input` / `send_message` drive them. Whatever you spawn is yours to `close_process` when done. When you `send_message` a sub-agent, its reply comes back into YOUR pane as `[sub-agent:<name>] …`, not into the sub-agent's output — to wait for it, use `timer_fire_when_idle_any([sub_agent])` and then read your own pane; do NOT `wait_for_pattern` on the sub-agent, that will deadlock until timeout."
const serverInstructions = "You are inside patterm. Use these MCP tools; do not launch patterm or poke its Unix socket yourself. Use spawn_agent for sub-agents, close spawned panes when done, and use timer_fire_when_idle_* instead of wait_for_pattern to wait for send_message replies."
// toolDescriptor is the shape returned by `tools/list`. inputSchema is
// a JSON Schema object — we provide a minimal `{type: "object"}` schema
@@ -76,37 +78,41 @@ func objectSchema(properties map[string]any, required []string) map[string]any {
}
func stringProp(desc string) map[string]any {
return map[string]any{"type": "string", "description": desc}
_ = desc
return map[string]any{"type": "string"}
}
func numberProp(desc string) map[string]any {
return map[string]any{"type": "number", "description": desc}
_ = desc
return map[string]any{"type": "number"}
}
func integerProp(desc string) map[string]any {
return map[string]any{"type": "integer", "description": desc}
_ = desc
return map[string]any{"type": "integer"}
}
func booleanProp(desc string) map[string]any {
return map[string]any{"type": "boolean", "description": desc}
_ = desc
return map[string]any{"type": "boolean"}
}
func arrayOfStringsProp(desc string) map[string]any {
_ = desc
return map[string]any{
"type": "array",
"description": desc,
"items": map[string]any{"type": "string"},
"type": "array",
"items": map[string]any{"type": "string"},
}
}
// toolCatalog is the full list advertised via tools/list. Descriptions
// are intentionally short — clients are expected to fetch help() for
// detail. Schemas mirror the param structs in tools.go.
func toolCatalog() []toolDescriptor {
return []toolDescriptor{
func toolCatalog(role CallerRole) []toolDescriptor {
tools := []toolDescriptor{
{
Name: "spawn_agent",
Description: "Spawn a sub-agent from an agent preset and optionally seed it with initial instructions. This is the ONLY correct way to start a sub-agent under you — do not shell out to `claude` / `codex` / `opencode` and do not poke patterm's Unix socket via perl / nc / socat. Either bypasses caller identity and the new agent lands as a stray top-level tab instead of your child. Caller owns lifecycle: when the sub-agent's work is done (it reports back via send_message, or you no longer need it), call close_process on its process_id to free the pane and tear down the PTY. See help('spawning') and help('lifecycle').",
Description: "Spawn a sub-agent from an agent preset.",
InputSchema: objectSchema(map[string]any{
"agent": stringProp("Preset name (e.g. \"claude\", \"codex\")."),
"agent_instructions": stringProp("Initial prompt typed into the agent after it's ready."),
@@ -115,14 +121,14 @@ func toolCatalog() []toolDescriptor {
},
{
Name: "spawn_process",
Description: "Spawn a process: a terminal, a process preset, or a freeform argv command. Caller owns lifecycle: when the process is no longer needed, call close_process to remove its entry (live children are SIGKILL'd first). See help('lifecycle').",
Description: "Spawn a terminal, process preset, or argv command.",
InputSchema: objectSchema(map[string]any{
"kind": stringProp("\"terminal\" or \"command\"."),
"preset": stringProp("Process preset name (mutually exclusive with argv)."),
"argv": map[string]any{"type": "array", "items": map[string]any{"type": "string"}, "description": "Argv vector for freeform commands."},
"argv": map[string]any{"type": "array", "items": map[string]any{"type": "string"}},
"name": stringProp("Display name for the pane."),
"working_dir": stringProp("Working directory for the spawned process."),
"env": map[string]any{"type": "object", "additionalProperties": map[string]any{"type": "string"}, "description": "Extra environment variables."},
"env": map[string]any{"type": "object", "additionalProperties": map[string]any{"type": "string"}},
"shell": booleanProp("Run argv through sh -lc."),
}, nil),
},
@@ -188,7 +194,9 @@ func toolCatalog() []toolDescriptor {
{
Name: "get_project_status",
Description: "One-shot orientation: project, caller, processes, scratchpads.",
InputSchema: objectSchema(nil, nil),
InputSchema: objectSchema(map[string]any{
"include_tools": booleanProp("Include available_tools in caller metadata."),
}, nil),
},
{
Name: "get_process_output",
@@ -197,6 +205,7 @@ func toolCatalog() []toolDescriptor {
"process_id": stringProp("Target process id."),
"mode": stringProp("\"grid\" (default) or \"stream\"."),
"since_offset": integerProp("Watermark offset from a previous call."),
"max_bytes": integerProp("Maximum content bytes to return."),
}, []string{"process_id"}),
},
{
@@ -205,6 +214,7 @@ func toolCatalog() []toolDescriptor {
InputSchema: objectSchema(map[string]any{
"process_id": stringProp("Target process id."),
"since_offset": integerProp("Byte offset from a previous call."),
"max_bytes": integerProp("Maximum content bytes to return."),
}, []string{"process_id"}),
},
{
@@ -214,12 +224,13 @@ func toolCatalog() []toolDescriptor {
"process_id": stringProp("Target process id."),
"pattern": stringProp("Regex pattern."),
"kind": stringProp("\"rendered\" (default) or \"raw\"."),
"limit": integerProp("Max matches (default 20)."),
"limit": integerProp("Max matches (default 10)."),
"max_bytes": integerProp("Max bytes per returned match line."),
}, []string{"process_id", "pattern"}),
},
{
Name: "wait_for_pattern",
Description: "Block until pattern appears in the TARGET process's own output, or timeout elapses. Use this for waiting on text the target itself will emit (a shell prompt, a build's \"tests passed\" line, etc.). Anti-pattern: do NOT use this to wait for a sub-agent's reply to send_message — replies are routed into the CALLER's pane tagged `[sub-agent:<name>]`, not into the sub-agent's output, so this call will spin to timeout. For sub-agent coordination use `timer_fire_when_idle_any` and then read your own pane.",
Description: "Block until pattern appears in the target process output.",
InputSchema: objectSchema(map[string]any{
"process_id": stringProp("Target process id."),
"pattern": stringProp("Regex pattern."),
@@ -238,18 +249,19 @@ func toolCatalog() []toolDescriptor {
Name: "send_input",
Description: "Type text, paste a block, or fire a named key into a process. Optional tail-after-send.",
InputSchema: objectSchema(map[string]any{
"process_id": stringProp("Target process id."),
"kind": stringProp("\"text\", \"paste\", or \"key\"."),
"text": stringProp("Text payload for kind=text/paste."),
"key": stringProp("Named key for kind=key (e.g. \"enter\", \"escape\")."),
"submit": booleanProp("Whether to append a submit keystroke."),
"wait_ms": integerProp("After sending, wait this many ms before tailing."),
"tail_mode": stringProp("\"none\" (default), \"stream\", or \"grid\"."),
"process_id": stringProp("Target process id."),
"kind": stringProp("\"text\", \"paste\", or \"key\"."),
"text": stringProp("Text payload for kind=text/paste."),
"key": stringProp("Named key for kind=key (e.g. \"enter\", \"escape\")."),
"submit": booleanProp("Whether to append a submit keystroke."),
"wait_ms": integerProp("After sending, wait this many ms before tailing."),
"tail_mode": stringProp("\"none\" (default), \"stream\", or \"grid\"."),
"tail_max_bytes": integerProp("Maximum bytes in returned tail."),
}, []string{"process_id", "kind"}),
},
{
Name: "send_message",
Description: "Deliver a text message to another process as orchestrator-owned input. Fire-and-forget: returns immediately, without waiting for the recipient to read or act. If the recipient replies via send_message, that reply arrives in YOUR pane tagged `[sub-agent:<name>]` (child→parent) or `[orchestrator]` (parent→child) — NOT in the recipient's output. To wait for a sub-agent's reply, schedule `timer_fire_when_idle_any([sub_agent_id], body=…)` and then read your own pane when the timer fires. Do not `wait_for_pattern` on the recipient for a reply; it will deadlock.",
Description: "Send a tagged message to a parent or child process.",
InputSchema: objectSchema(map[string]any{
"target_process_id": stringProp("Recipient process id."),
"message": stringProp("Message body."),
@@ -283,7 +295,7 @@ func toolCatalog() []toolDescriptor {
},
{
Name: "timer_fire_when_idle_any",
Description: "Canonical way to wait for a sub-agent to finish working: send_message the sub-agent, then schedule this with watched=[sub_agent_id]; when it fires, the reply is already sitting in your own pane tagged `[sub-agent:<name>]`. Schedules a timer that fires when any watched process enters idle (already-idle entries excluded), or when max_wait_seconds elapses.",
Description: "Fire when any watched process becomes idle.",
InputSchema: objectSchema(map[string]any{
"watched": arrayOfStringsProp("Process ids to watch."),
"body": stringProp("Message delivered verbatim to the owning agent when the timer fires."),
@@ -294,7 +306,7 @@ func toolCatalog() []toolDescriptor {
},
{
Name: "timer_fire_when_idle_all",
Description: "Canonical way to wait for several sub-agents to finish working in parallel: send_message each one, then schedule this with watched=[…ids]; when it fires, each reply is in your own pane tagged `[sub-agent:<name>]`. Schedules a timer that fires when all watched processes are idle (already-idle entries count as satisfied), or when max_wait_seconds elapses.",
Description: "Fire when all watched processes are idle.",
InputSchema: objectSchema(map[string]any{
"watched": arrayOfStringsProp("Process ids to watch."),
"body": stringProp("Message delivered verbatim to the owning agent when the timer fires."),
@@ -338,7 +350,9 @@ func toolCatalog() []toolDescriptor {
Name: "scratchpad_read",
Description: "Read a scratchpad entry, returning content and revision.",
InputSchema: objectSchema(map[string]any{
"name": stringProp("Scratchpad name."),
"name": stringProp("Scratchpad name."),
"offset": integerProp("Byte offset to start reading."),
"max_bytes": integerProp("Maximum content bytes to return."),
}, []string{"name"}),
},
{
@@ -367,8 +381,10 @@ func toolCatalog() []toolDescriptor {
},
{
Name: "whoami",
Description: "Return the caller's identity, role, parent, project metadata, and available tools.",
InputSchema: objectSchema(nil, nil),
Description: "Return caller identity, role, parent, and project metadata.",
InputSchema: objectSchema(map[string]any{
"include_tools": booleanProp("Include full available tool list."),
}, nil),
},
{
Name: "help",
@@ -378,6 +394,16 @@ func toolCatalog() []toolDescriptor {
}, nil),
},
}
if role != RoleSubAgent {
return tools
}
filtered := tools[:0]
for _, tool := range tools {
if tool.Name != "spawn_agent" {
filtered = append(filtered, tool)
}
}
return filtered
}
// handleProtocolMethod handles MCP protocol-level methods. Returns
@@ -416,7 +442,14 @@ func (s *Server) handleProtocolMethod(callerID, method string, params json.RawMe
return map[string]any{}, true, 0, "", nil
case "tools/list":
return map[string]any{"tools": toolCatalog()}, true, 0, "", nil
role := RoleOrchestrator
s.mu.Lock()
host := s.host
s.mu.Unlock()
if host != nil {
role = host.CallerRole(callerID)
}
return map[string]any{"tools": toolCatalog(role)}, true, 0, "", nil
case "tools/call":
var p struct {
@@ -472,25 +505,12 @@ func (s *Server) handleProtocolMethod(callerID, method string, params json.RawMe
return nil, false, 0, "", nil
}
// wrapToolResult turns a structured tool result into an MCP tools/call
// response. Plain strings (e.g. "ok") become text content; structured
// values are JSON-encoded into a single text block and also exposed
// under structuredContent so capable clients can read the shape.
// wrapToolResult turns a tool result into an MCP tools/call response.
// Structured values are exposed once under structuredContent; content
// carries only a short model-readable summary to avoid duplicating
// large JSON payloads into the transcript.
func wrapToolResult(result any) map[string]any {
var text string
switch v := result.(type) {
case nil:
text = "ok"
case string:
text = v
default:
b, err := json.Marshal(v)
if err != nil {
text = fmt.Sprintf("%v", v)
} else {
text = string(b)
}
}
text := summarizeToolResult(result)
out := map[string]any{
"content": []map[string]any{{"type": "text", "text": text}},
"isError": false,
@@ -505,3 +525,70 @@ func wrapToolResult(result any) map[string]any {
}
return out
}
func summarizeToolResult(result any) string {
switch v := result.(type) {
case nil:
return "ok"
case string:
return v
case ProcessInfo:
return fmt.Sprintf("%s %s %s", v.ID, v.Kind, v.Status)
case []ProcessInfo:
return fmt.Sprintf("%d processes", len(v))
case ProcessStatus:
return fmt.Sprintf("%s %s %s", v.ID, v.Kind, v.Status)
case ProjectStatus:
return fmt.Sprintf("%d processes, %d scratchpads", len(v.Processes), len(v.Scratchpads))
case ProcessOutput:
return outputSummary(v.Mode, v.ContentBytes, v.Truncated, v.NewOffset)
case RawOutput:
return outputSummary("raw", v.ContentBytes, v.Truncated, v.NewOffset)
case SearchResult:
if v.Truncated {
return fmt.Sprintf("%d matches (truncated)", len(v.Matches))
}
return fmt.Sprintf("%d matches", len(v.Matches))
case SendInputResult:
if v.Tail != nil {
return "ok; tail included"
}
return "ok"
case TimerHandle:
return "timer " + v.ID
case TimerFireWhenIdleResponse:
if v.ID != "" {
return fmt.Sprintf("%s timer %s", v.Status, v.ID)
}
return v.Status
case []TimerInfo:
return fmt.Sprintf("%d timers", len(v))
case []scratchpad.Entry:
return fmt.Sprintf("%d scratchpads", len(v))
case ScratchpadReadResult:
if v.Truncated {
return fmt.Sprintf("%d/%d bytes from offset %d", v.ContentBytes, v.TotalBytes, v.Offset)
}
return fmt.Sprintf("%d bytes", v.ContentBytes)
case WhoAmI:
if v.ProcessID == "" {
return string(v.Role)
}
return fmt.Sprintf("%s %s", v.ProcessID, v.Role)
case HelpResponse:
return fmt.Sprintf("help: %s", v.Topic)
default:
return "ok"
}
}
func outputSummary(mode string, bytes int, truncated bool, offset int64) string {
s := fmt.Sprintf("%s output: %d bytes", mode, bytes)
if offset > 0 {
s += fmt.Sprintf(", offset %d", offset)
}
if truncated {
s += " (truncated)"
}
return s
}

View File

@@ -2,6 +2,7 @@ package mcp
import (
"encoding/json"
"strings"
"testing"
)
@@ -43,6 +44,9 @@ func TestInitializeReturnsCapabilities(t *testing.T) {
if !ok || instructions == "" {
t.Fatalf("instructions missing or wrong type: %+v", parsed.Result)
}
if len(instructions) > 320 {
t.Fatalf("instructions too verbose: %d chars", len(instructions))
}
}
func TestInitializedNotificationSuppressesResponse(t *testing.T) {
@@ -74,6 +78,9 @@ func TestToolsListReturnsConcreteSchemas(t *testing.T) {
if parsed.Error != nil {
t.Fatalf("tools/list returned error: %+v", parsed.Error)
}
if len(resp) > 12000 {
t.Fatalf("tools/list response too large: %d bytes", len(resp))
}
tools, ok := parsed.Result["tools"].([]interface{})
if !ok {
t.Fatalf("tools not array: %+v", parsed.Result)
@@ -112,6 +119,27 @@ func TestToolsListReturnsConcreteSchemas(t *testing.T) {
}
}
func TestWrapToolResultDoesNotDuplicateStructuredJSON(t *testing.T) {
result := ProcessOutput{
Content: strings.Repeat("x", 1024),
Mode: "stream",
NewOffset: 2048,
ContentBytes: 1024,
}
wrapped := wrapToolResult(result)
if wrapped["structuredContent"] == nil {
t.Fatalf("structuredContent missing: %#v", wrapped)
}
content := wrapped["content"].([]map[string]any)
text := content[0]["text"].(string)
if strings.Contains(text, result.Content) {
t.Fatalf("content duplicated structured payload: %q", text)
}
if !strings.Contains(text, "stream output") {
t.Fatalf("summary text should identify output, got %q", text)
}
}
func TestPingReturnsEmptyObject(t *testing.T) {
s := &Server{}
req := []byte(`{"jsonrpc":"2.0","id":3,"method":"ping"}`)

View File

@@ -74,10 +74,10 @@ type ToolHost interface {
// Inspection.
ListProcesses(callerID, kindFilter string) []ProcessInfo
GetProcessStatus(callerID, processID string) (ProcessStatus, error)
GetProjectStatus(callerID string) (ProjectStatus, error)
GetProcessOutput(callerID, processID, mode string, sinceOffset int64) (ProcessOutput, error)
GetProcessRawOutput(callerID, processID string, sinceOffset int64) (RawOutput, error)
SearchOutput(callerID, processID, pattern, kind string, limit int) (SearchResult, error)
GetProjectStatus(callerID string, includeTools bool) (ProjectStatus, error)
GetProcessOutput(callerID string, args ProcessOutputArgs) (ProcessOutput, error)
GetProcessRawOutput(callerID string, args RawOutputArgs) (RawOutput, error)
SearchOutput(callerID string, args SearchOutputArgs) (SearchResult, error)
WaitForPattern(callerID, processID, pattern string, timeoutSeconds float64, scope string) (matched bool, snippet string, err error)
GetProcessPorts(callerID, processID string) ([]PortSighting, error)
@@ -98,13 +98,13 @@ type ToolHost interface {
// Scratchpads.
ScratchpadList() ([]scratchpad.Entry, error)
ScratchpadRead(name string) (content string, revision string, err error)
ScratchpadRead(args ScratchpadReadArgs) (ScratchpadReadResult, error)
ScratchpadWrite(name, content, expectedRevision string) (revision string, err error)
ScratchpadAppend(name, content string) error
ScratchpadDelete(name string) error
// Meta.
WhoAmI(callerID string) WhoAmI
WhoAmI(callerID string, includeTools bool) WhoAmI
Help(callerID, topic string) HelpResponse
}
@@ -157,6 +157,10 @@ type ProjectStatus struct {
Scratchpads []scratchpad.Entry `json:"scratchpads"`
}
type ProjectStatusArgs struct {
IncludeTools bool `json:"include_tools"`
}
// ProjectMeta is the project root info echoed in many payloads.
type ProjectMeta struct {
Path string `json:"path"`
@@ -166,23 +170,42 @@ type ProjectMeta struct {
// ProcessOutput is the get_process_output payload. SPEC §7 enriches
// the old read_output result with screen geometry + version.
type ProcessOutput struct {
Content string `json:"content"`
Mode string `json:"mode"`
NewOffset int64 `json:"new_offset,omitempty"`
ActiveScreen string `json:"active_screen,omitempty"`
Rows int `json:"rows,omitempty"`
Cols int `json:"cols,omitempty"`
Cursor Cursor `json:"cursor"`
IdleMS int64 `json:"idle_ms,omitempty"`
Status string `json:"status,omitempty"`
ScreenVersion int64 `json:"screen_version,omitempty"`
Content string `json:"content"`
Mode string `json:"mode"`
NewOffset int64 `json:"new_offset,omitempty"`
ActiveScreen string `json:"active_screen,omitempty"`
Rows int `json:"rows,omitempty"`
Cols int `json:"cols,omitempty"`
Cursor Cursor `json:"cursor"`
IdleMS int64 `json:"idle_ms,omitempty"`
Status string `json:"status,omitempty"`
ScreenVersion int64 `json:"screen_version,omitempty"`
ContentBytes int `json:"content_bytes,omitempty"`
Truncated bool `json:"truncated,omitempty"`
TruncatedBytes int `json:"truncated_bytes,omitempty"`
}
type ProcessOutputArgs struct {
ProcessID string `json:"process_id"`
Mode string `json:"mode"`
SinceOffset int64 `json:"since_offset"`
MaxBytes int `json:"max_bytes"`
}
// RawOutput is the get_process_raw_output payload — ANSI preserved.
type RawOutput struct {
Content string `json:"content"`
NewOffset int64 `json:"new_offset"`
Status string `json:"status,omitempty"`
Content string `json:"content"`
NewOffset int64 `json:"new_offset"`
Status string `json:"status,omitempty"`
ContentBytes int `json:"content_bytes,omitempty"`
Truncated bool `json:"truncated,omitempty"`
TruncatedBytes int `json:"truncated_bytes,omitempty"`
}
type RawOutputArgs struct {
ProcessID string `json:"process_id"`
SinceOffset int64 `json:"since_offset"`
MaxBytes int `json:"max_bytes"`
}
// SearchResult is search_output's payload.
@@ -191,6 +214,14 @@ type SearchResult struct {
Truncated bool `json:"truncated"`
}
type SearchOutputArgs struct {
ProcessID string `json:"process_id"`
Pattern string `json:"pattern"`
Kind string `json:"kind"`
Limit int `json:"limit"`
MaxBytes int `json:"max_bytes"`
}
type SearchMatch struct {
LineNo int `json:"line_no"`
Text string `json:"text"`
@@ -245,6 +276,7 @@ type TimerInfo struct {
ID string `json:"timer_id"`
Label string `json:"label,omitempty"`
Body string `json:"body,omitempty"`
BodyTruncated bool `json:"body_truncated,omitempty"`
Kind string `json:"kind"` // "delay" | "idle_any" | "idle_all"
Status string `json:"status"` // "pending" | "paused"
OwnerID string `json:"owner_process_id"`
@@ -281,13 +313,14 @@ type SpawnProcessArgs struct {
// SendInputArgs is the input shape for send_input — covers text /
// paste / key with the optional wait+tail tail-after-send.
type SendInputArgs struct {
ProcessID string `json:"process_id"`
Kind string `json:"kind"` // "text" | "paste" | "key"
Text string `json:"text"`
Key string `json:"key"`
Submit *bool `json:"submit"`
WaitMS int `json:"wait_ms"`
TailMode string `json:"tail_mode"` // "none" | "stream" | "grid"
ProcessID string `json:"process_id"`
Kind string `json:"kind"` // "text" | "paste" | "key"
Text string `json:"text"`
Key string `json:"key"`
Submit *bool `json:"submit"`
WaitMS int `json:"wait_ms"`
TailMode string `json:"tail_mode"` // "none" | "stream" | "grid"
TailMaxBytes int `json:"tail_max_bytes"`
}
// SendInputResult is the return shape of send_input.
@@ -306,6 +339,27 @@ type WhoAmI struct {
AvailableTools []string `json:"available_tools"`
}
type WhoAmIArgs struct {
IncludeTools bool `json:"include_tools"`
}
type ScratchpadReadArgs struct {
Name string `json:"name"`
Offset int `json:"offset"`
MaxBytes int `json:"max_bytes"`
}
type ScratchpadReadResult struct {
Content string `json:"content"`
Revision string `json:"revision"`
Offset int `json:"offset,omitempty"`
NextOffset int `json:"next_offset,omitempty"`
ContentBytes int `json:"content_bytes,omitempty"`
TotalBytes int `json:"total_bytes,omitempty"`
Truncated bool `json:"truncated,omitempty"`
TruncatedBytes int `json:"truncated_bytes,omitempty"`
}
// HelpResponse is the help return shape.
type HelpResponse struct {
Topic string `json:"topic"`
@@ -507,61 +561,51 @@ func callTool(h ToolHost, callerID, method string, params json.RawMessage) (any,
return st, 0, "", nil
case "get_project_status":
ps, err := h.GetProjectStatus(callerID)
var p ProjectStatusArgs
_ = unmarshalParamsOptional(params, &p)
ps, err := h.GetProjectStatus(callerID, p.IncludeTools)
if err != nil {
return mapToolError(err)
}
return ps, 0, "", nil
case "get_process_output":
var p struct {
ProcessID string `json:"process_id"`
Mode string `json:"mode"`
SinceOffset int64 `json:"since_offset"`
}
var p ProcessOutputArgs
if err := unmarshalParams(params, &p); err != nil {
return nil, codeInvalidParams, err.Error(), nil
}
if p.Mode == "" {
p.Mode = "grid"
}
out, err := h.GetProcessOutput(callerID, p.ProcessID, p.Mode, p.SinceOffset)
out, err := h.GetProcessOutput(callerID, p)
if err != nil {
return mapToolError(err)
}
return out, 0, "", nil
case "get_process_raw_output":
var p struct {
ProcessID string `json:"process_id"`
SinceOffset int64 `json:"since_offset"`
}
var p RawOutputArgs
if err := unmarshalParams(params, &p); err != nil {
return nil, codeInvalidParams, err.Error(), nil
}
out, err := h.GetProcessRawOutput(callerID, p.ProcessID, p.SinceOffset)
out, err := h.GetProcessRawOutput(callerID, p)
if err != nil {
return mapToolError(err)
}
return out, 0, "", nil
case "search_output":
var p struct {
ProcessID string `json:"process_id"`
Pattern string `json:"pattern"`
Kind string `json:"kind"`
Limit int `json:"limit"`
}
var p SearchOutputArgs
if err := unmarshalParams(params, &p); err != nil {
return nil, codeInvalidParams, err.Error(), nil
}
if p.Limit <= 0 {
p.Limit = 20
p.Limit = 10
}
if p.Kind == "" {
p.Kind = "rendered"
}
res, err := h.SearchOutput(callerID, p.ProcessID, p.Pattern, p.Kind, p.Limit)
res, err := h.SearchOutput(callerID, p)
if err != nil {
return mapToolError(err)
}
@@ -731,17 +775,15 @@ func callTool(h ToolHost, callerID, method string, params json.RawMessage) (any,
return entries, 0, "", nil
case "scratchpad_read":
var p struct {
Name string `json:"name"`
}
var p ScratchpadReadArgs
if err := unmarshalParams(params, &p); err != nil {
return nil, codeInvalidParams, err.Error(), nil
}
content, rev, err := h.ScratchpadRead(p.Name)
res, err := h.ScratchpadRead(p)
if err != nil {
return nil, codeInternal, err.Error(), nil
}
return map[string]any{"content": content, "revision": rev}, 0, "", nil
return res, 0, "", nil
case "scratchpad_write":
var p struct {
@@ -790,7 +832,9 @@ func callTool(h ToolHost, callerID, method string, params json.RawMessage) (any,
return map[string]any{"ok": true}, 0, "", nil
case "whoami":
return h.WhoAmI(callerID), 0, "", nil
var p WhoAmIArgs
_ = unmarshalParamsOptional(params, &p)
return h.WhoAmI(callerID, p.IncludeTools), 0, "", nil
case "help":
var p struct {