eval-analysis

name	eval-analysis
description	Analyze eval results to understand signal quality and guide prompt/config changes. Use when the user says "eval-analysis", "analyze eval results", "what do the evals show", "eval regression", or asks about eval signal enrichment.

/eval-analysis

Structured methodology for analyzing eforge eval results, identifying signal patterns, and proposing changes with anti-bias safeguards.

Prerequisites

• The eval harness MCP server must be connected (provides eval_runs, eval_observations, eval_scenario_detail, eval_run, eval_results tools)
• You should be in or have access to the eforge project codebase

Workflow

Step 1: Gather Recent Eval Data

Start by checking what eval data is available:

1. Use eval_runs to list recent eval runs. Note run IDs, timestamps, and which scenarios were included.
2. If the user mentions a specific run or comparison, use eval_results with the relevant run ID(s).
3. If comparing baseline vs candidate, use eval_results with the compare parameter to get a structured regression comparison between two runs.

Step 2: Pull Observations

For runs of interest, use eval_observations to get detailed per-scenario observation data. This gives you the raw signal - scores, pass/fail, and any metadata attached to each observation.

Focus on:

• Scenarios with low scores or failures
• Scenarios where scores changed significantly between runs
• Patterns across scenario categories

Step 3: Drill Into Affected Scenarios

For each scenario showing issues or regressions, use eval_scenario_detail to get the full scenario specification - inputs, expected outputs, scoring criteria, and any notes.

This is critical context: you need to understand what the scenario tests before reasoning about why it failed.

Step 4: Read Relevant Source

Before forming hypotheses about root cause, always read the relevant eforge prompt or config file that the failing scenarios exercise. Do not guess at prompt content from memory.

Common locations:

• Agent prompts: src/engine/prompts/*.md
• Agent implementations: src/engine/agents/*.ts
• Config and defaults: src/engine/config.ts
• Schema definitions: src/engine/schemas.ts
• Pipeline stages: src/engine/pipeline.ts

Understanding the actual prompt/config text is essential for accurate root cause analysis.

Step 5: Apply Anti-Bias Gating Rules

Before proposing any change based on eval data, check every proposed action against all five gating rules. A proposal that violates any rule must be revised or dropped.

Rule 1: Never Reduce Sensitivity

Do not propose changes that would make the system less sensitive to errors, edge cases, or subtle signals. If a scenario is failing because the agent catches something it previously missed, that may be a feature, not a bug. Reducing sensitivity to make numbers go up is a false improvement.

Rule 2: Never Shift Threshold in One Direction

Do not propose adjusting a threshold, cutoff, or scoring boundary that only moves it in one direction (e.g., making pass criteria more lenient, or raising a tolerance). Any threshold change must be justified by evidence that the current threshold is wrong in both directions - too strict in some cases AND too lenient in others - or must be accompanied by a new scenario that tests the boundary from the other side.

Rule 3: Always Require Counter-Scenario

For any proposed behavior change, identify at least one existing scenario (or propose a new one) that would regress if the change were applied incorrectly. If you cannot identify a counter-scenario, the change is under-constrained and should not be made until one exists. The counter-scenario proves the change is targeted rather than a broad relaxation.

Rule 4: Prefer Scenario Additions Over Behavior Changes

When eval results reveal a gap, the first response should be "do we need a new scenario?" not "do we need to change the prompt?" Adding scenarios that capture the desired behavior is lower-risk than modifying prompts or config. Only propose behavior changes when the scenario coverage is already adequate and the root cause is clearly in the prompt/config.

Rule 5: Respect Confidence Thresholds

Do not propose changes based on small sample sizes or marginal differences. Require:

• At least 3 observations of a pattern before treating it as signal (not noise)
• A score difference of at least 10% between baseline and candidate to call it a regression or improvement
• If a scenario has high variance across runs, flag it as unreliable rather than acting on its latest result

Step 6: Formulate Findings

Present findings conversationally with three components for each issue:

1. Data - What the eval numbers show. Quote specific scores, scenario names, and run IDs. Show the delta if comparing runs.
2. Hypothesis - What you think is causing the observed behavior, grounded in the source you read in Step 4. Be explicit about confidence level (high/medium/low) and what evidence supports or weakens the hypothesis.
3. Proposed Action - What to do about it. This must pass all five gating rules. Clearly label whether the action is:
   • Add scenario - New eval scenario to improve coverage
   • Modify prompt/config - Change to eforge source (with specific file and section)
   • Investigate further - Need more data before acting
   • No action - Signal is noise or expected behavior

Step 7: Regression Gate (for candidate comparison)

When comparing a candidate change against a baseline:

1. Use eval_results with the compare parameter to get the structured comparison.
2. Flag any scenario that regressed by more than 10% as a blocker.
3. For each regression, trace through Steps 3-5 to determine if the regression is:
   • Real - The candidate change broke something. Block the change.
   • Flaky - The scenario has high variance. Flag but don't block.
   • Expected - The candidate intentionally changes behavior the scenario tests. Update the scenario.
4. Summarize with a clear PASS/BLOCK recommendation.

Step 8: Run New Evals (if needed)

If the analysis suggests running a new eval (e.g., after adding scenarios or to get more data):

1. Use eval_run to kick off a new run.
2. Wait for completion, then loop back to Step 1 with the new run data.

Important Reminders

• Always read source before reasoning about root cause (Step 4)
• Every proposed change must pass all five gating rules (Step 5)
• Present findings as data + hypothesis + action (Step 6)
• When in doubt, propose adding scenarios rather than changing behavior (Rule 4)
• Small sample sizes are noise, not signal (Rule 5)