| name | blast-radius |
| description | Pre-flight protocol for missions that modify, remove, rename, or alter the semantics of existing symbols on fleet-generator. Documents call-site impact and required updates BEFORE code changes are made. |
| when_to_use | Mission renames or removes a symbol. Mission changes a function signature. Mission deprecates a method. Mission alters schema fields, enum cases, or shared constants. Trigger phrases: blast radius, MUST_UPDATE, INTENTIONALLY_LEFT, RESCOPE_REQUIRED, rename, signature change, symbol removal, deprecation, migration, orphan deprecation, bridge helper, partial migration, call sites. |
| status | active |
| tags | ["skill"] |
| updated | 2026-05-07T00:00:00.000Z |
Blast Radius Discipline
Right the first time, every time. A partial migration is worse than
a delayed migration.
When this skill applies
Before the worker makes any change to existing code that modifies,
removes, renames, deprecates, or alters the semantics of a symbol
that may be referenced elsewhere. Specifically, any of:
- Renaming a type, function, parameter, or field
- Changing a function signature (parameters, types, return)
- Removing a property, parameter, accessor, or case
- Adding deprecation annotations
- Changing semantics even when the signature is preserved
- Modifying schema, persistence, or canonical constants
Does NOT apply to purely additive changes: new files with no
references yet, new private helpers, formatting, comment-only edits.
If uncertain whether a change triggers this skill — it does. Run the
protocol.
The protocol — five steps
Step 0: Establish the baseline
Before writing any production code:
<your-test-runner> 2>&1 | tail -5
If tests don't pass at mission start, STOP. Tests must pass at the
baseline. Fix in a separate mission first.
Step 1: Identify every symbol being changed
For each symbol the mission will modify:
- Full path
- Change class: rename / signature / removal / deprecation / semantic
- Scope: public / internal / private
Step 2: Grep exhaustively
For each symbol, grep across all of: production code, tests, docs,
configs, comments. See references/grep-recipes.md
for language-specific patterns.
For renamed symbols, grep BOTH old and new names to confirm the old
has no surviving references.
Step 3: Classify every hit
Every grep hit gets one of three classifications:
- MUST_UPDATE — uses the symbol; must change to match
- INTENTIONALLY_LEFT — false positive OR legitimate non-update.
Requires written justification.
- RESCOPE_REQUIRED — must update, but doing so expands the
mission beyond its sanctioned scope. The mission stops. Surface
to the human with a rescope request.
The RESCOPE_REQUIRED classification is the escape valve. The wrong
move is to silence the issue with a bridge or shim — see
references/anti-patterns.md.
Step 4: Write the Blast Radius Report
Commit it to docs/blast_radius/<mission-id>_BLAST_RADIUS.md as
the FIRST commit of the work, before any production change. Use the
template in references/report-template.md.
Step 5: Implement — every MUST_UPDATE site must be touched
When implementation begins, every file listed as MUST_UPDATE must
appear in the final diff. Garfield verifies this in post-flight.
The rule
If a change to symbol X has any effect on other code that reads or
writes X, every such call site is in scope. There is no
"pre-existing, out of scope" escape hatch for call sites of the SAME
symbol.
If the mission cannot cover all call sites, the mission rescopes —
it never ships partial.
