/memtrace-preflight

name: memtrace-preflight
description: "Run a one-call pre-flight check on a single existing symbol before editing it: blast radius, co-change partners, complexity, 30-day churn, and verification checklist, then check Cortex decision memory for rationale/bans when intent may matter. Use before modifying any existing function or symbol you did not just write. Do not start editing a non-trivial existing function without pre-flight plus decision-memory recall/provenance; Memtrace knows the dependency graph, change history, and recorded decisions."

Overview

Pre-flight check: the two minutes before an edit that prevent the bug. One `preflight_check` call composes the dependency graph, the bi-temporal change history, and the complexity metrics into an actionable radar for a single symbol.

Quick Reference

| Tool | Purpose | |------|---------| | `preflight_check` | Full radar for one symbol: blast radius + co-change + churn + checklist | | `get_impact` | Deeper blast-radius walk when the radar flags HIGH/CRITICAL | | `get_cochange_context` | Wider co-change window when partners look surprising | | `recall_decision` | Recorded choices, bans, and conventions for the symbol/subsystem/behavior | | `why_is_this_here` / `governing_contracts` | Symbol-scoped rationale and constraints when a symbol id is available |

> **Parameter types:** MCP parameters are strictly typed. Numbers must be

Full parameter spec for every Memtrace tool: `references/mcp-parameters.md` (bundled at the memtrace-skills plugin root). > JSON numbers — not strings.

Steps

1. Run the pre-flight check before touching the symbol

`preflight_check` with:

• `repo_id` — required
• `symbol` — the function/method name you are about to modify

2. Read the checklist — it is generated from the graph, not boilerplate

Each line names something concrete to verify:

• *"N symbols depend on this"* → run `get_impact` again after your edit and

compare `total_affected`; new dependents mean your change leaked wider than intended.

• *"hotspot: N changes in 30 days"* → keep the edit small and reviewable;

hot code punishes large diffs.

• *"sits in N process flow(s)"* → check the process steps still order

correctly after the change.

• *"last touched by agent session …"* → read the latest episode before

assuming the current shape is intentional.

3. Treat co-change partners as part of the change

Files that historically changed together with the target usually need updating in the same change. If you finish the edit without touching a frequent partner, say so explicitly and why.

4. After the edit, close the loop

• Re-run `preflight_check` (or `get_impact`) on the symbol.
• The complexity number should not have grown without a stated reason;

if it did, simplify before declaring the work done.

Cortex gate before editing

Before changing behavior, deleting code, or refactoring odd/legacy code:

1. Run `recall_decision("<symbol/subsystem/behavior>")`. 2. If the preflight/graph result gives you a numeric `symbol_id`, run `why_is_this_here(symbol_id)` and `governing_contracts(symbol_id)`. 3. Honor matching held decisions/bans. Treat CannotProve as unknown, not approval.

Verdict guidance

• `risk: CRITICAL/HIGH` — propose the change plan before editing; consider

a feature flag or staged rollout.

• `dependents: 0` — edit freely; note the symbol may be newly added or an

entry point.

• A matching Cortex decision/ban — surface it before editing and do not

contradict it without explicit user sign-off.

Output

`preflight_check` returns one radar for the symbol:

| Field | Meaning | |-------|---------| | `risk` | verdict, e.g. `HIGH` / `CRITICAL` (see Verdict guidance) | | `dependents` | blast radius — count of symbols that depend on the target | | co-change partners | files that historically change with it (step 3) | | complexity + 30-day churn | current complexity score and recent change count | | checklist | generated verification lines, e.g. `"hotspot: 6 changes in 30 days"`, `"sits in 2 process flow(s)"` |