Agent Skills: Evals — Assertion-First AI Evaluation

Objective eval metrics via code/model/human graders with pass@k/pass^k scoring. USE WHEN eval, evaluate, test agent, benchmark, verify behavior, regression test, capability test, run eval, compare models, compare prompts, create judge, create use case, view results, failure to task, suite manager, transcript capture, trial runner.

UncategorizedID: danielmiessler/personal_ai_infrastructure/Evals

Install this agent skill to your local

pnpm dlx add-skill https://github.com/danielmiessler/Personal_AI_Infrastructure/tree/HEAD/LifeOS/install/skills/Evals

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LifeOS/install/skills/Evals/SKILL.md

Skill Metadata

Name
Evals
Description
"Assertion-first AI eval framework aligned to Anthropic's 'Demystifying evals for AI agents' — typed deterministic asserts + a forced-structured LLM judge over an input→assert case schema, pass^k/pass@k, capability vs regression suites, subscription-billed. USE WHEN eval, evaluate, benchmark, regression test, assertion, assert, llm-rubric, judge, pass@k, pass^k, grade output, compare prompts/models, test agent. NOT FOR scientific-method framing (use Science), property/mutation testing of code (use Hardening), or live UI verification (use Interceptor)."

Evals — Assertion-First AI Evaluation

What it is

An eval gives an AI an input, then applies assertions to its output to measure success (Anthropic's definition). A case is {id, prompt, assert:[...]}. Each assertion is either deterministic (code, fast/free) or model-graded (an LLM judge). Cases run multiple trials; we report pass^k (all trials pass — the honest metric for a reliability-critical agent) and pass@k (any trial passes). Everything routes through Inference.ts — subscription-billed, no API-key path, no external deps.

Grounded in Anthropic's current doctrine — Demystifying evals for AI agents, Define success criteria / develop tests, and the skill-creator {text, passed, evidence} assertion convention. The typed-assert layer is promptfoo-shaped but our own TS.

The canonical path (v2)

| Tool | Role | |------|------| | Tools/Assertions.ts | Deterministic assert engine: equals, contains, icontains, contains-all/any, regex, starts-with, ends-with, is-json, contains-json, max-length, min-length, each with not- negation. Sync, no model call. | | Tools/Judge.ts | Model-graded asserts llm-rubric (1–5 → 0–1, threshold) and llm-assert (NL assertions → TRUE/FALSE/UNKNOWN). Forced-structured JSON verdict, reason-then-score, distinct judge level, Unknown→miss escape hatch. | | Tools/EvalRunner.ts | Loads a suite, runs the agent-under-test per case (single-shot inference against the target system prompt), applies asserts, computes pass^k/pass@k, persists transcripts + latest.json. | | Tools/SuiteManager.ts | Suite listing + saturation tracking. | | Tools/FailureToTask.ts | Convert real failures into cases (seed from 20–50 real failures). |

# Run a suite (USER-customization suites resolve before the skill's own)
bun run ${LIFEOS_SKILL_DIR}/Tools/EvalRunner.ts -s <suite> [-t trials] [--json]
# Sanity-check the assert engine / judge
bun run ${LIFEOS_SKILL_DIR}/Tools/Assertions.ts     # 16-case self-test
bun run ${LIFEOS_SKILL_DIR}/Tools/Judge.ts          # good-vs-bad discrimination

Workflow Routing

| Workflow | Trigger | File | |----------|---------|------| | RunEval | "run the eval", "run suite", "evaluate this", "grade output" | Workflows/RunEval.md | | CreateUseCase | "new eval", "create a suite", "eval for X", "what should I test" | Workflows/CreateUseCase.md | | CreateJudge | "write a judge", "llm-rubric", "grading criteria", "judge prompt" | Workflows/CreateJudge.md | | ComparePrompts | "compare prompts", "which prompt is better", "A/B this prompt" | Workflows/ComparePrompts.md | | CompareModels | "compare models", "which model is better", "is the cheaper rung enough" | Workflows/CompareModels.md | | ViewResults | "eval results", "how did it score", "show the last run", "saturation" | Workflows/ViewResults.md | | CreateScenario | "create a scenario", "multi-turn eval", "scenario test" | Workflows/CreateScenario.md | | RunScenario | "run the scenario", "run multi-turn" | Workflows/RunScenario.md |

Suite / case schema (assertion-first)

name: my-suite
type: regression            # or capability
pass_threshold: 0.75
agent_level: medium         # agent-under-test inference level
judge_level: high           # judge != generator (Anthropic best practice)
trials: 3
# system_prompt: optional override; default = live system prompt + DA identity
cases:
  - id: descriptive_name
    prompt: "the user turn sent to the agent-under-test"
    assert:
      - type: not-contains       # deterministic
        value: "should work"
        weight: 1
      - type: llm-rubric         # model-graded, weighted for partial credit
        weight: 2
        value: "Does the output tie any done-claim to verification evidence?"
      - type: llm-assert
        weight: 1
        value: ["The output does not claim success without evidence"]
  - id: should_not_case          # balance: test should-do AND should-not
    negative: true
    prompt: "..."
    assert: [...]

Identity-bound suites (e.g. {{DA_NAME}}'s dispositions) live in LIFEOS/USER/CUSTOMIZATIONS/SKILLS/Evals/Suites/ — the public skill ships only generic suites/examples.

Doctrine (from Anthropic — encode, don't restate)

  • Grade the output/outcome, not the path. Tool-call-sequence asserts are brittle and demoted to opt-in; the everyday suite grades what the agent produced. The legacy core-behaviors suite (tool-sequence graded) is retained only as an example of this anti-pattern.
  • Capability starts low (a hill to climb); regression targets ~100%; passing capability cases graduate into regression.
  • pass^k for reliability, pass@k where one success suffices.
  • Partial credit via assert weights. Balance should-do and should-not cases — one-sided evals create one-sided optimization.
  • Judge discipline: distinct judge model, reason-then-score, forced structured verdict, an Unknown escape hatch.
  • Never trust a score until you read transcripts — every run persists full case transcripts to MEMORY/STATE/Evals-Results/<suite>/<run>/run.json.

Harness integration

  • Config-change regression: hooks/ConfigEvalFire.hook.tsLIFEOS/TOOLS/ConfigEvalOnChange.ts fires the configured dispositions suite when a behaviour-defining file changes (default core-behaviors; override via LIFEOS/USER/CUSTOMIZATIONS/SKILLS/Evals/config.json config_change_suite — identity-bound suites live in that USER layer, never the public tree); regressions notify Pulse. Non-blocking, subscription-billed, debounced.
  • ISA / Algorithm: an eval suite is the operational form of an ISA claim's falsifier — see LIFEOS/MEMORY/WORK/20260716-eval-system-integration/ISA.md for the integration map.

Legacy (v1, superseded)

The v1 grader-stack (Graders/, TrialRunner.ts) and the @langwatch/scenario path (ScenarioRunner.ts, LifeosAgentAdapter.ts, API-billed) predate the assertion-first rewrite. Prefer the v2 path above. The scenario path bills ANTHROPIC_API_KEY — do not use it for principal work.

Gotchas

  • Single-shot agent-under-test narrates tool calls. Running the full agentic system prompt through tool-less inference makes the agent defer and simulate tool use instead of answering — which tanks "lead with the answer" style cases. EvalRunner injects an [EVALUATION CONTEXT] no tools, answer directly suffix to fix this; keep it when authoring output-graded disposition cases.
  • judge_level must differ from agent_level (Anthropic: judge ≠ generator). Default agent=medium, judge=high.
  • Unknown counts as a miss. A judge that can't verify an assertion returns UNKNOWN, scored as fail — conservative for regression, correct for gates.
  • Deterministic asserts are free; use them first. Reserve model asserts (llm-rubric/llm-assert) for nuance a code check can't capture.
  • is-json checks the whole output; contains-json checks for an embedded fragment. Don't use is-json on prose that merely mentions JSON.

Execution Log

After completing any workflow, append a single JSONL entry:

echo '{"ts":"'$(date -u +%Y-%m-%dT%H:%M:%SZ)'","skill":"Evals","workflow":"WORKFLOW_USED","input":"8_WORD_SUMMARY","status":"ok|error","duration_s":SECONDS}' >> ~/.claude/LIFEOS/MEMORY/SKILLS/execution.jsonl