| name | mechanistic-interventions |
| description | Use when moving from benchmark-driven analysis into causal or mechanism-oriented interventions. Covers activation patching, interchange, control design, read-vs-write distinctions, and intervention-specific success criteria, while pointing to future attention and routing follow-up work. |
Mechanistic Interventions
Use this skill when the user wants to:
- design causal intervention experiments after readout/localization work
- plan activation patching or interchange tests
- decide whether a readable signal is also writable
- structure intervention controls and success criteria
- review whether an intervention claim is too strong for the evidence
This skill is the interventions phase of the benchmark-flow pipeline.
It begins after:
- latent labels are validated
- the benchmark analysis has a site hypothesis
- readout/localization evidence exists
This skill owns:
- intervention framing
- site-choice hypothesis
- donor-target pairing and control design
- success and failure criteria
- planning-time interpretation heuristics
It does not own:
- patch operator choice
- layer sweep execution
- flip-rate computation
- execution-time interpretation of specific patching results
Those belong to:
Core rule
A readable signal is not automatically a writable signal.
Do not treat a high-AUROC probe or clean direction as sufficient evidence for causal importance.
What this skill owns
1. Intervention framing
Define:
- exact behavior to change
- success criteria
- malformed-output criteria
- intended direction of change
2. Site choice from the computation story
Choose intervention sites because:
- localization suggests them
- timing suggests them
- the computation is still live there
Not because:
- they are easy to patch
- they are the best probe layer
3. Paired design and controls
Prefer:
- matched donor-target pairs
- single-layer first tests
- same-label controls
- random or unmatched controls when useful
4. Interpretation discipline
Track:
- intended-direction flips
- reverse-direction flips
- malformed outputs
- same-label instability
Separate:
- causal evidence
- broad destabilization
- late summary-state corruption
Planning-time heuristics to keep in mind:
- if the same tiny set of rows always flips, suspect borderline sensitivity rather than broad causal control
- if late-layer patching produces garbage, suspect compressed summary-state corruption
- if a mean-swap patch does almost nothing, suspect a lossy operator before abandoning the hypothesis
5. Follow-on mechanism work
This skill should also point to likely next steps:
- attention follow-up
- routing / MoE follow-up
- narrower span decomposition
- read-vs-write comparisons
Those may later justify dedicated skills, but this phase should at least surface them.
References
Primary reference:
Related references:
Use activation-patching-causal-evals as the main methodology library here.
Use the shared principles doc for:
- read layer vs write layer
- evidence ladder
- claim shaping discipline
Required artifacts
At minimum, leave behind:
workspaces/<workspace>/[<thread>/]phase_04/docs/04-intervention-plan.md
the main human-readable intervention plan, including:
- intervention target behavior
- success metrics
- interpretation caveats
- likely next mechanism-focused analyses
workspaces/<workspace>/[<thread>/]phase_04/docs/04-site-hypothesis.md
why these intervention sites are plausible
workspaces/<workspace>/[<thread>/]phase_04/docs/04-pairing-and-controls.md
donor-target design, same-label controls, and failure criteria
workspaces/<workspace>/[<thread>/]phase_04/docs/04-intervention-summary.json
compact structured summary of intervention target, sites, controls, and next actions
Use simple frontmatter on markdown artifacts:
benchmark
phase
version
frozen_date
input_artifacts
Someone inspecting this phase should be able to answer:
- what behavior the intervention is supposed to change
- why the chosen site is plausible
- what counts as success vs destabilization
- what technique skill should be invoked next
Handoff
If the intervention design is weak because the benchmark lacks proper contrasts:
If the intervention plan is sound:
Update the benchmark sidecar with:
- intervention candidates
- planning-time failure-mode cautions
- what mechanism follow-up looks most justified next