fix(mcp): slim instructions to <2KB, enrich tool descriptions, add IDs to hook by wcatz · Pull Request #139 · wcatz/ghost

wcatz · 2026-04-01T12:13:23Z

Problem

mcpInstructions was 3,232 bytes. Claude Code truncates at 2KB, silently dropping the Project IDs, Cross-Project, and Tasks sections. This is why Claude never knows how to handle project_id or cross-project saves.

Changes

Instructions (3,232 → 1,625 bytes):

Moved category list + importance scale to ghost_memory_save description
Moved cross-project guidance into instructions (was being truncated)
Added explicit project_id anchor ("use project name from hook heading")
Added "never pass raw filesystem paths" guidance

Tool descriptions:

Added concrete examples to memory_save, memory_search, save_global, decision_record
Added FTS5 syntax examples to search query schema
Improved all project_id schemas with examples (e.g. 'ghost', 'infra')
Differentiated ghost_memories_list from ghost_memory_search
Added when-to-use guidance to delete, pin, decisions_list

Hook output:

Added Use project_id: "ghost" for all ghost_* tool calls.
Memory IDs now shown ([architecture] \6BDC098A` ...`)
Task IDs now shown ([active] \F2A46791` P3 ...`)
Memory count shown ("25 shown")

Bug fix:

ghost_task_create priority defaulted to P0 (critical) when omitted due to Go int zero value. Now uses *int pointer, defaults to P2 (normal).

Test plan

go test ./... — all pass
Hook output verified: project_id anchor, memory IDs, task IDs
Instructions measured at 1,625 bytes (under 2KB limit)

Summary by CodeRabbit

New Features
- Task creation accepts optional priority with automatic defaulting when omitted.
Improvements
- Memory listings now show identifiers and visibility counts for easier reference.
- Open tasks display identifiers and include optional description lines when present.
- System guidance and tool documentation updated for clearer cross-project and workflow behavior.

…s to hook mcpInstructions was 3,232 bytes — Claude Code truncates at 2KB, silently dropping the Project IDs, Cross-Project, and Tasks sections. Changes: - Slim instructions from 3,232 to 1,625 bytes (under 2KB limit) - Move category list, importance scale to ghost_memory_save description - Add concrete examples to 5 most-used tool descriptions - Add FTS5 syntax examples to search query jsonschema - Improve all project_id jsonschema tags with examples - Add explicit project_id anchor to hook output header - Include memory IDs and task IDs in hook output - Show memory count in hook ("25 shown") - Add cross-project save guidance to instructions - Fix priority zero-value bug: omitted priority now defaults to P2 (was silently P0 critical due to Go int zero value)

coderabbitai · 2026-04-01T12:13:38Z

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📝 Walkthrough

Walkthrough

SessionStart hook output and session-context loading were changed: the hook emits a "## Ghost context" header with project_id guidance and reformats memories/tasks to include truncated IDs; loadSessionContext now returns memories and tasks tuples with added ID/description elements. MCP server instructions and tool schemas were updated; task priority became optional.

Changes

Cohort / File(s)	Summary
Hook Output & Context Loading `internal/mcpinit/hook.go`	Rewrote `HandleSessionStartHook` to emit the "## Ghost context" header (no trailing blank line), add a project_id instruction line for ghost_* tool calls, render memories as (`shortID`) with category/content and label as `Memories (N shown)`, and render tasks with truncated `id` and optional description only when present. `loadSessionContext` tuple shapes changed: `memories` tuples now include `id` as the first element; `tasks` tuples include a fourth element for optional description. Added `shortID` helper.
MCP Instructions & Tool Schemas `internal/mcpserver/mcpserver.go`	Replaced `mcpInstructions` content to emphasize proactive `ghost_memory_save`, clarify SessionStart context loading, and update `project_id` guidance (use project name vs paths; examples). Updated JSON schema descriptions across multiple ghost_* tools to reflect "project_id as project name" guidance. Changed `ghost_task_create` `priority` parameter from `int` to `*int` (optional) and added local defaulting before passing to `s.store.CreateTask`.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

docs(readme): update counts and add mcp init safety note #137: Implements SessionStart hook and session-context updates that add task/decision IDs and new fields — directly related to the tuple and rendering changes here.
feat(mcp): phase 1 — new tools, resources, enriched hook #136: Modifies HandleSessionStartHook and loadSessionContext shapes; overlaps with the DB query and tuple-layout updates in this diff.
fix(mcp): prevent duplicate projects from raw path IDs #138: Adjusts SessionStart hook outputs/tests to accept the updated "Ghost context" header and formatting; test-level changes correspond to this PR's output changes.

Poem

🐇 I hopped in with IDs trimmed to eight,

Memories lined up, tidy and straight.
Tasks with whispers of descriptions small,
Project names guiding each ghostly call.
A carrot for code — organized, not late.

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 60.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the three main changes: reducing MCP instructions to under 2KB, enriching tool descriptions, and adding IDs to the hook output.

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Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@internal/mcpinit/hook.go`:
- Line 62: The code is slicing IDs with m[0][:8] (seen in the fmt.Fprintf call
that formats "- [%s] `%s` %s\n") which will panic for IDs shorter than 8; update
both occurrences (the one using m[1], m[0][:8], m[2] and the similar occurrence
around line 198) to safely compute a prefix: if len(m[0]) >= 8 use m[0][:8] else
use m[0] (or a small helper like shortID(id string) string) and use that value
in the fmt.Fprintf calls so short IDs do not cause runtime panics.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

Push a commit to this branch (recommended)
Create a new PR with the fixes

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: d17b37d9-97f7-41de-af61-92b3d7d87561

📥 Commits

Reviewing files that changed from the base of the PR and between 2ce4edf and 3f67c80.

📒 Files selected for processing (2)

internal/mcpinit/hook.go
internal/mcpserver/mcpserver.go

coderabbitai Bot reviewed Apr 1, 2026

View reviewed changes

Comment thread internal/mcpinit/hook.go Outdated

fix(hook): guard ID slicing against short IDs

9edd9c2

wcatz merged commit 738ada6 into main Apr 1, 2026
4 of 5 checks passed

wcatz deleted the fix/mcp-prompt-overhaul branch April 1, 2026 12:24

coderabbitai Bot mentioned this pull request Apr 18, 2026

fix(mcp): path prefix false-match, optional task status, global limit, URI tests #148

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fix(mcp): slim instructions to <2KB, enrich tool descriptions, add IDs to hook#139

fix(mcp): slim instructions to <2KB, enrich tool descriptions, add IDs to hook#139
wcatz merged 2 commits intomainfrom
fix/mcp-prompt-overhaul

wcatz commented Apr 1, 2026 •

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wcatz commented Apr 1, 2026 •

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