[Investigation] Use when quickly locating relevant files and affected areas across a large codebase.
execution-mode
subagent
context-budget
medium
[BLOCKING] Execute skill steps in declared order. NEVER skip, reorder, or merge steps without explicit user approval.
[BLOCKING] Before each step or sub-skill call, update task tracking: set in_progress when step starts, set completed when step ends.
[BLOCKING] Every completed/skipped step MUST include brief evidence or explicit skip reason.
[BLOCKING] If Task tools are unavailable, create and maintain an equivalent step-by-step plan tracker with the same status transitions.
Quick Summary
Goal: Deliver a complete, prioritized map of every file relevant to the task via fast, parallel codebase discovery — grep + graph combined — so downstream work starts with full coverage and zero blind spots.
Summary:
Classify scope FIRST (Phase 0: backend/frontend/full-stack) so you spawn only the agents you need — never the default 3 when the prompt names one layer.
Sub-agents do the parallel grep/glob; only YOU (main agent) run the graph commands afterward — graph expansion on 2-3 key files is MANDATORY when .code-graph/graph.db exists and is the step that finds what grep can't.
This is discovery, not analysis: return prioritized file paths fast (3-5 min), no content deep-dives — that's investigate's job.
If <5 files surface, re-examine keywords and run a second pass with broader synonyms before synthesizing.
Graph Expand (MANDATORY — DO NOT SKIP) — MUST ATTENTION run graph commands on 2-3 key files. Graph reveals complete dependency network grep CANNOT find.
Low-Result Check — If <5 files returned, re-examine keywords and run second pass
Synthesize — Combine grep + graph into numbered, prioritized file list
Key Rules:
Speed over depth — return file paths only, no content analysis
Target 3-5 minutes total; 3-minute timeout per agent
NEVER skip graph expansion when .code-graph/graph.db exists
--ext / --engine=external switches the search engine to the scout-external agent (gemini/opencode CLIs); default is internal subagents
Scout — Fast Codebase File Discovery
Phase 0: Classify Search Scope
Before spawning agents, classify request:
Scope
Detection
Agent Strategy
Backend-only
server-side class names, domain entities, API handlers
Agents 1+2, skip Agent 3
Frontend-only
component names, client-side source, UI features
Agent 3 only
Full-stack
Feature name spanning both layers
All 3 agents
Unknown
Ambiguous prompt
Default all 3 agents
Think: Prompt mention specific layer? Entity exist in backend, frontend, or both? Adjust agent count — avoid spawning unnecessary agents.
When to Use
Quickly locating relevant files across large codebase
Beginning work on features spanning multiple directories
Before changes affecting multiple parts
Mapping file landscape before investigation or implementation
NOT for: Deep code analysis (use investigate), debugging (use debug-investigate), implementation (use workflow-feature).
Workflow
Step 1: Analyze Search Request
Extract from USER_PROMPT:
Entity names (User, Customer, Order)
Feature names (authentication, notification)
File types needed (backend, frontend, or both)
Step 2: Execute Parallel Search
Spawn SCALE number of scout subagents in parallel via Agent tool (subagent_type: "scout").
WHY scout not Explore: Custom scout agents read .claude/agents/scout.md — includes graph CLI knowledge + Bash access. Built-in Explore agents have NO graph awareness.
Engine Selection (--ext / --engine=external)
Detect the engine flag in args (default: internal):
Internal (default): spawn subagent_type: "scout" — the parallel grep/glob/graph search described below.
External (--ext or --engine=external): spawn subagent_type: "scout-external" instead. That agent (.claude/agents/scout-external.md) owns the gemini/opencode CLI dispatch, the Explore fallback, and the install prompt when those CLIs are absent.
Flag only switches which subagent runs. Orchestration identical for both engines: Phase 0 classify, Step 3 graph-expand (run by you, main agent), low-result check, synthesize. Output contract (numbered, prioritized file list) same.
Per agent: 3-minute timeout. Return file paths only — no content analysis. Use Glob (patterns), Grep (content), Bash (graph CLI).
Step 3: Graph Expand (MANDATORY — DO NOT SKIP)
YOU (main agent) MUST ATTENTION run graph commands YOURSELF after sub-agents return. NOT optional — without graph, results are incomplete. Sub-agents cannot use graph — only main agent can.
If GRAPH_AVAILABLE, pick 2-3 key files from sub-agent results (entities, commands, bus messages):
# Full dependency network of key file
python .claude/scripts/code_graph connections <key_file> --json
# All callers of key command/handler
python .claude/scripts/code_graph query callers_of <FunctionName> --json
# All importers of bus message class
python .claude/scripts/code_graph query importers_of <file_path> --json
# Batch query multiple files (most efficient)
python .claude/scripts/code_graph batch-query <file1> <file2> <file3> --json
# If graph returns "ambiguous" — disambiguate first
python .claude/scripts/code_graph search <keyword> --kind Function --json
# Trace shortest path between two nodes
python .claude/scripts/code_graph find-path <source_qn> <target_qn> --json
# Filter by service, limit results
python .claude/scripts/code_graph query callers_of <name> --limit 5 --filter "ServiceName" --json
Grep-First Discovery (semantic queries): When prompt describes behavior/flow (not specific file), grep key terms FIRST to discover entry files, then use those as graph input:
Grep class names, commands, handlers, endpoints
Use discovered files as input to connections, batch-query, or trace
Use trace --direction both on middle files (controllers, commands) for full upstream + downstream
Graph results get HIGHER priority than grep — structural relationships > text matches. After graph expansion, grep again to verify content in discovered files.
Post-Grep Trace Trigger: whenever a grep/glob surfaces an important entry-point file — an entity, command, query, event/command handler, controller, bus message/consumer, component, store, or api-service — immediately run a graph trace on it before concluding. The trace reveals callers, consumers, bus messages, event chains, and tests that grep CANNOT find: python .claude/scripts/code_graph trace <key-entry-file> --direction both --json. Pattern: grep finds files → graph trace reveals full system flow → grep verifies specific details.
Step 4: Low-Result Check
If total files found <5 after Steps 2-3:
Re-examine keywords — too specific? Try broader synonyms
Spawn second scout agent with alternate search terms
Try python .claude/scripts/code_graph search <keyword> --json to find nodes by name
Step 5: Synthesize Results
Combine grep + graph into numbered, prioritized file list (see Results Format).
Search Patterns by Priority
Substitute folder names + file globs from the project's structure reference / docs/project-config.json. {backend-source-glob} / {frontend-source-glob} are the per-stack source extensions.
Execute /scout directly — run this skill standalone
Next Steps
MANDATORY MUST ATTENTION — NO EXCEPTIONS after completing, MUST ATTENTION use AskUserQuestion to present:
"/investigate (Recommended)" — Deep-dive into discovered files
"/plan" — If scouted files sufficient to start planning
"Skip, continue manually" — user decides
[IMPORTANT] Use TaskCreate to break ALL work into small tasks BEFORE starting — including tasks for each file read. This prevents context loss from long files. For simple tasks, AI MUST ATTENTION ask user whether to skip.
docs/project-reference/domain-entities-reference.md — Domain entity catalog, relationships, cross-service sync (read when task involves business entities/models)
External Memory: Complex/lengthy work → write findings incrementally to plans/reports/. Prevents context loss.
Evidence Gate: MANDATORY MUST ATTENTION — every claim, finding, recommendation requires file:line proof with confidence % (>80% act, <80% verify first).
Graph-Assisted Investigation — MANDATORY when .code-graph/graph.db exists.
HARD-GATE: MUST ATTENTION run at least ONE graph command on key files before concluding any investigation.
Pattern: Grep finds files → trace --direction both reveals full system flow → Grep verifies details
Task
Minimum Graph Action
Investigation/Scout
trace --direction both on 2-3 entry files
Fix/Debug
callers_of on buggy function + tests_for
Feature/Enhancement
connections on files to be modified
Code Review
tests_for on changed functions
Blast Radius
trace --direction downstream
CLI:python .claude/scripts/code_graph {command} --json. Use --node-mode file first (10-30x less noise), then --node-mode function for detail.
Incremental Result Persistence — MANDATORY for all sub-agents or heavy inline steps processing >3 files.
Before starting: Create report file plans/reports/{skill}-{date}-{slug}.md
After each file/section reviewed: Append findings to report immediately — never hold in memory
Return to main agent: Summary only (per SYNC:subagent-return-contract) with Full report: path
Main agent: Reads report file only when resolving specific blockers
Why: Context cutoff mid-execution loses ALL in-memory findings. Each disk write survives compaction. Partial results are better than no results.
Sub-Agent Return Contract — When this skill spawns a sub-agent, the sub-agent MUST return ONLY this structure. Main agent reads only this summary — NEVER requests full sub-agent output inline.
Main agent reads Full report file ONLY when: (a) resolving a specific blocker, or (b) building a fix plan.
Sub-agent writes full report incrementally (per SYNC:incremental-persistence) — not held in memory.
Context budget — the return payload is a SUMMARY, not a transcript: ≤10 finding bullets, no raw file contents / full diffs / verbatim logs inline, no re-pasted source. Everything beyond the summary lives in the Full report on disk. A sub-agent that would exceed the summary shape MUST write the detail to its report and return only the pointer — the orchestrator's context is the scarce resource the whole map-reduce protects.
Nested Task Expansion Contract — For workflow-step invocation, the [Workflow] ... row is only a parent container; the child skill still creates visible phase tasks.
Call TaskList first. If a matching active parent workflow row exists, set nested=true and record parentTaskId; otherwise run standalone.
Create one task per declared phase before phase work. When nested, prefix subjects [N.M] $skill-name — phase.
When nested, link the parent with TaskUpdate(parentTaskId, addBlockedBy: [childIds]).
Orchestrators must pre-expand a child skill's phase list and link the workflow row before invoking that child skill or sub-agent.
Mark exactly one child in_progress before work and completed immediately after evidence is written.
Complete the parent only after all child tasks are completed or explicitly cancelled with reason.
Blocked until:TaskList done, child phases created, parent linked when nested, first child marked in_progress.
Project Reference Docs Gate — Run after task-tracking bootstrap and before target/source file reads, grep, edits, or analysis. Project docs override generic framework assumptions.
Identify scope: file types, domain area, and operation.
Read every required doc. If docs/project-config.json, the docs index, lessons.md, CLAUDE.md, AGENTS.md, or any task-required reference doc is missing or stale, auto-run /project-init or the narrow lower-level route (/project-config, /docs-init, /scan-all, /scan --target=<key>, /claude-md-init) before ordinary project-specific work. If Codex mirrors or AGENTS.md are missing/stale, ask the user to run /sync-codex; do not auto-run it.
Before target work, state: Reference docs read: ... | Not applicable: ....
Task Tracking & External Report Persistence — Bootstrap this before execution; then run project-reference doc prefetch before target/source work.
Create a small task breakdown before target file reads, grep, edits, or analysis. On context loss, inspect the current task list first.
Mark one task in_progress before work and completed immediately after evidence; never batch transitions.
For plan/review work, create plans/reports/{skill}-{YYMMDD}-{HHmm}-{slug}.md before first finding.
Append findings after each file/section/decision and synthesize from the report file at the end.
Final output cites Full report: plans/reports/{filename}.
Blocked until: task breakdown exists, report path declared for plan/review work, first finding persisted before the next finding.
Critical Thinking Mindset — Apply critical thinking, sequential thinking. Every claim needs traced proof, confidence >80% to act.
Anti-hallucination: Never present guess as fact — cite sources for every claim, admit uncertainty freely, self-check output for errors, cross-reference independently, stay skeptical of own confidence — certainty without evidence root of all hallucination.
Evidence-Based Reasoning — Speculation is FORBIDDEN. Every claim needs proof.
Cite file:line, grep results, or framework docs for EVERY claim
Declare confidence: >80% act freely, 60-80% verify first, <60% DO NOT recommend
Cross-service validation required for architectural changes
"I don't have enough evidence" is valid and expected output
BLOCKED until:- [ ] Evidence file path (file:line) - [ ] Grep search performed - [ ] 3+ similar patterns found - [ ] Confidence level stated
Forbidden without proof: "obviously", "I think", "should be", "probably", "this is because"
If incomplete → output: "Insufficient evidence. Verified: [...]. Not verified: [...]."
Cross-Service Check — Microservices/event-driven: MANDATORY before concluding investigation, plan, spec, or feature doc. Missing downstream consumer = silent regression.
Rationalization Prevention — AI skips steps via these evasions. Recognize and reject:
Evasion
Rebuttal
"Too simple for a plan"
Simple + wrong assumptions = wasted time. Plan anyway.
"I'll test after"
RED before GREEN. Write/verify test first.
"Already searched"
Show grep evidence with file:line. No proof = no search.
"Just do it"
Still need TaskCreate. Skip depth, never skip tracking.
"Just a small fix"
Small fix in wrong location cascades. Verify file:line first.
"Code is self-explanatory"
Future readers need evidence trail. Document anyway.
"Combine steps to save time"
Combined steps dilute focus. Each step has distinct purpose.
AI Mistake Prevention — Failure modes to avoid on every task:
Re-read files after context changes. Context compaction, resume, or long-running work can make memory stale; verify current files before acting.
Verify generated content against source evidence. AI hallucinates APIs, names, claims, and document facts. Check the relevant source before documenting or referencing.
Check downstream references before deleting or renaming. Removing an artifact can stale docs, generated mirrors, configs, and callers; map references first.
Trace the full impact chain after edits. Changing a definition can miss derived outputs and consumers. Follow the affected chain before declaring done.
Verify ALL affected outputs, not just the first. One green check is not all green checks; validate every output surface the change can affect.
Assume existing values are intentional — ask WHY before changing. Before changing a constant, limit, flag, wording, or pattern, read nearby context and history.
Surface ambiguity before acting — don't pick silently. Multiple valid interpretations require an explicit question or stated assumption with risk.
Keep shared guidance role-relevant. Universal guidance must help every receiving skill or agent; code-specific obligations belong only in code-specific protocols.
MUST ATTENTION cite file:line evidence for every claim. Confidence >80% to act, <60% = do NOT recommend.
MUST ATTENTION never skip steps via evasions. Plan anyway. Test first. Show grep evidence with file:line.
MUST ATTENTION run at least ONE graph command on key files before concluding when .code-graph/graph.db exists.
MUST ATTENTION apply critical + sequential thinking — every claim needs appropriate traced evidence (file:line for repo/code claims; source URL or artifact section for research, product, content, and docs claims); confidence >80% to act, <60% DO NOT recommend. Anti-hallucination: never present guess as fact, admit uncertainty freely, cross-reference independently, stay skeptical of own confidence.
MUST ATTENTION apply AI mistake prevention — verify generated content against evidence, trace downstream references before deleting or renaming, verify all affected outputs, re-read files after context loss, and surface ambiguity before acting.
MANDATORY Bootstrap task tracking before target work; transition one task at a time.
MANDATORY Persist plan/review findings to plans/reports/ incrementally and synthesize from disk.
MANDATORY After task-tracking bootstrap and before target/source work, read required project-reference docs and cite Reference docs read: ....
MANDATORY Always include lessons.md; project conventions override generic defaults.
MANDATORY If project config, root instruction files, or any required reference doc is missing or stale, auto-run /project-init or the narrow lower-level route before ordinary project-specific work.
MANDATORY Parent workflow rows do not replace child phase tracking; expand phases and link the parent when nested.
MANDATORY Orchestrators pre-expand child skill phases before invocation; use [N.M] $skill-name — phase prefixes and one-in_progress discipline.
Prompt-Enhance Closing Anchors
IMPORTANT MUST ATTENTION follow declared step order for this skill; NEVER skip, reorder, or merge steps without explicit user approval
IMPORTANT MUST ATTENTION for every step/sub-skill call: set in_progress before execution, set completed after execution
IMPORTANT MUST ATTENTION every skipped step MUST include explicit reason; every completed step MUST include concise evidence
IMPORTANT MUST ATTENTION if Task tools unavailable, maintain an equivalent step-by-step plan tracker with synchronized statuses
Closing Reminders
IMPORTANT MUST ATTENTION Goal: Deliver a complete, prioritized map of every file relevant to the task — grep + graph combined — so downstream work starts with full coverage and zero blind spots.
IMPORTANT MUST ATTENTION — Protocols in force (concise digest of the SYNC/shared blocks this skill carries; each is a signpost to its canonical body above):
Graph-Assisted Investigation: Run one graph command on key files before concluding.
Incremental Persistence: Append findings to a report file, never hold in memory.
Subagent Return Contract: Sub-agents return summary only, full report on disk.
Nested Task Creation: Expand child phases and link parent when nested.
Critical Thinking: Traced proof per claim, confidence >80% to act.
Evidence: Cite file:line; speculation forbidden, <60% do not recommend.
Cross-Service Check: Scan producers, consumers, sagas, contracts for silent regressions.
Rationalization Prevention: Reject step-skipping evasions; show grep evidence.
AI Mistake Prevention: verify generated content against evidence, trace downstream references, verify all affected outputs, re-read after context loss, surface ambiguity.
MUST ATTENTION every protocol above is in force for this scout — honor its canonical body, not just the digest line.
IMPORTANT MUST ATTENTION run Phase 0 classification BEFORE spawning agents — scope (backend/frontend/full-stack) determines agent count; never spawn the default 3 when the prompt names one layer — why: extra agents waste budget and dilute focus
IMPORTANT MUST ATTENTION graph expand is the MANDATORY step that finds what grep cannot — run at least ONE graph command (connections/callers_of/trace --direction both) on 2-3 key files when .code-graph/graph.db exists; NEVER skip it — why: structural relationships > text matches, and sub-agents cannot run graph — only you can
IMPORTANT MUST ATTENTION cite file:line evidence for every claim. Confidence >80% to act, <60% = DO NOT recommend — why: speculation seeds blind spots downstream work inherits
MUST ATTENTION stay in DISCOVERY lane — return prioritized file paths fast (3-5 min), no content deep-dives; that is investigate's job — why: scope creep into analysis breaks the 3-5 min budget and duplicates the next step
MUST ATTENTION if <5 files found, re-examine keywords and run a second pass with broader synonyms BEFORE synthesizing — why: a thin result is an under-searched result, not a small surface
MUST ATTENTION run a post-grep graph trace whenever grep surfaces an entry-point file (entity, command, query, handler, controller, bus message, component, store, api-service) — trace reveals callers/consumers/event chains/tests grep cannot find — why: missing a downstream consumer = silent regression for the next step
MUST ATTENTION spawn scout/scout-external subagents — NOT built-in Explore — why: only the custom agents carry graph CLI knowledge + Bash access
MUST ATTENTION sub-agents return a SUMMARY only (≤10 finding bullets + Full report: path), writing full findings incrementally to plans/reports/ — NEVER hold all results in memory or request full sub-agent output inline — why: context cutoff mid-run loses every in-memory finding; disk writes survive compaction
MUST ATTENTION bootstrap task tracking BEFORE target work — TaskList first on context loss, one task in_progress at a time, expand child phases when nested under a workflow row — why: compaction wipes prior-work memory; resume from state, never duplicate
MUST ATTENTION read required project-reference docs (always lessons.md; domain-entities-reference.md for business entities) BEFORE searching — project conventions override generic framework assumptions
MUST ATTENTION use AskUserQuestion after completing (investigation workflow vs standalone, then /investigate vs /plan vs skip) — NEVER auto-proceed to the next step — why: the user owns scope; assuming standalone skips the workflow they wanted
MUST ATTENTION for non-trivial bug/regression scouts, surface End-to-Start trace candidates (reader → storage → writer → consumer → producer) and enumerate every feeder path — why: starting at the first suspicious file collapses multiple producers into one false "flow"
Anti-Rationalization:
Evasion
Rebuttal
"Graph step too slow, skip it"
Graph finds what 50 greps miss. NEVER skip when graph.db exists.
"Only 2 files, no need for report"
Incremental write costs nothing. Skip = context loss risk.
"Scope obvious, skip Phase 0"
Wrong agent set = missed files. Classify scope first, every time.
"Already searched, results complete"
Show grep + graph evidence with file:line. No proof = incomplete.
"Use Explore, it's a built-in"
Explore has NO graph awareness. Spawn scout/scout-external only.
"<5 files, surface is just small"
Thin result = under-searched. Broaden synonyms and re-pass before synth.
"I'll deep-dive these files now"
Discovery only — paths fast, no analysis. Deep-dive is investigate's job.
"Simple scout, skip workflow question"
User decides scope. NEVER assume standalone is acceptable.
IMPORTANT MUST ATTENTION Phase 0 classify first · graph expand is MANDATORY (never skip when graph.db exists) · cite file:line with confidence >80% — these three survive any long context, anchored top and bottom.
[TASK-PLANNING] Before acting, analyze task scope and systematically break it into small todo tasks and sub-tasks using TaskCreate.