Document the Logfire HTTP query path in the eval-debugging skill

The skill assumed the Logfire MCP is loaded. It is not loaded in every
session, which left no way to inspect a run at all. Document the HTTP query
API as the fallback, including the mandatory min_timestamp, the API keys
replacing read tokens, and the project-scoping trap: a key for the wrong
project authenticates and returns zero rows rather than erroring.

Also record three things that produced wrong readings in practice:
assertions/scores/metrics are keys inside the attributes column rather than
columns, one exception is emitted once per span level so failures must be
counted at case level, and assertion_pass_rate drops unjudged cases from its
denominator so judged and floor rates have to be quoted together.

Add a section for monitoring a run that is still in flight, since an eval
prints nothing until it finishes: case-span progress, the serial-execution
check that makes an ETA valid, and the per-case diagnostic attributes.

Vendor the query helper next to the skill so it does not point at a path
outside the repo, and derive its region from the key prefix.
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Yiorgis Gozadinos 2026-08-24 00:08:59 +03:00
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@ -1,6 +1,6 @@
---
name: debug-evals
description: Debug haiku.rag evaluation runs in Logfire. Use when asked to look at Logfire for an eval run, find failing or low-scoring eval cases, compare runs, check citation quality (cited_map) or judge pass rate (answer_equivalent), or explain why an eval case failed. Drives the Logfire MCP against the `evals` service.
description: Debug haiku.rag evaluation runs in Logfire. Use when asked to look at Logfire for an eval run, find failing or low-scoring eval cases, compare runs, check citation quality (cited_map) or judge pass rate (answer_equivalent), or explain why an eval case failed. Drives the Logfire MCP against the `evals` service, or the Logfire HTTP query API when the MCP is not loaded. Also covers monitoring a run that is still in flight.
---
# Debug eval runs in Logfire
@ -22,6 +22,72 @@ single case. Read-only.
4. Hand back a clickable trace with
`mcp__logfire__project_logfire_link(trace_id, project="haiku")`.
## When the Logfire MCP is not available
The `mcp__logfire__*` tools are not loaded in every session. The HTTP query API is
the fallback and needs no MCP:
```
POST https://logfire-eu.pydantic.dev/v2/query # EU projects
POST https://logfire-us.pydantic.dev/v2/query # US projects
Authorization: Bearer <api-key>
Content-Type: application/json
{"sql": "...", "min_timestamp": "2026-08-23T00:00:00Z"}
```
- **`min_timestamp` is mandatory** and silently bounds every result. Too recent a
value is indistinguishable from "no data".
- Read tokens are being replaced by **API keys** (`pylf_v2_<region>_...`). Same
`Authorization: Bearer` header; the region is in the prefix.
- Keep the key in `~/.logfire-read-key` (mode 600) and read it from there so it never
lands in a transcript. Helper next to this skill: `.claude/skills/debug-evals/lf-query.sh "<SQL>" [min_ts]`.
- The API is **project-scoped**. A key for the wrong project authenticates fine and
returns zero rows — it does not error. Diagnose in this order:
1. wrong region → `HTTP 401 Invalid read token` on the other host;
2. wrong project → auth succeeds, `count(*)` over months is 0;
3. right project → `SELECT service_name, count(*) ... GROUP BY service_name` shows
`evals`, `haiku-rag`, `haiku-ingester`.
Eval runs live in project **`haiku`**. There is an empty project named `evals`,
which is the natural wrong guess.
- **The API caps returned rows and does not say so.** Aggregate server-side
(`count(*)`, `avg(...)`, `sum(CASE WHEN ...)`) rather than pulling rows and counting
them locally. A pass rate computed from a clipped page is wrong and looks fine.
### JSON access via the HTTP API
`assertions`, `scores`, `metrics` and `case_name` are **keys inside the `attributes`
column, not columns** — `SELECT assertions` fails with `column not found`. Both of
these work:
```sql
attributes->'assertions'->'answer_equivalent' -- returns JSON
json_get_bool(attributes,'assertions','answer_equivalent','value')
json_get_float(attributes,'scores','cited_map','value')
json_get_int(attributes,'attributes','n_searches')
json_get_str(attributes,'attributes','citation_status')
```
Prefer the `json_get_*` form inside aggregates — it yields a typed value, so no cast
is needed and `sum(CASE WHEN ...)` behaves.
## Counting cases, not spans
**One exception appears once per span level.** A single failing case emits the same
`exception_type` on `case: {case_name}`, `execute {task}` and `invoke_agent agent`
(and often `chat {model}`), so a raw count over-reports by 3-4x. Always add
`AND span_name='case: {case_name}'` when counting failures. Cross-check that the
number equals the count of unjudged cases.
## Always report floor as well as judged
`assertion_pass_rate` **excludes unjudged cases from the denominator**, so cases that
died produce no verdict and silently inflate the headline. Report both:
- judged rate = passed / (cases - unjudged)
- floor = passed / cases
A run with 4.5% deaths reads ~3pp better than it is. Quote them together, always.
## Vocabulary
A run is one experiment span; its cases are direct children sharing its
@ -152,3 +218,78 @@ SELECT DISTINCT otel_scope_name, span_name
FROM records WHERE service_name='evals'
ORDER BY 1,2;
```
## Monitoring a run that is still in flight
An eval prints nothing until it finishes, so a live run's only progress signal is its
case spans. Everything below works mid-run.
Progress and ETA:
```sql
SELECT count(*) AS cases_done,
min(start_timestamp) AS first_case,
max(start_timestamp) AS latest_case,
avg(duration) AS avg_case_s
FROM records
WHERE service_name='evals' AND span_name='case: {case_name}'
AND start_timestamp > '<RUN_LAUNCH_TS>';
```
**Cases run serially**, so `ETA_total = total_cases * avg_case_s`. Verify rather than
assume: wall-clock per case (`latest_case - first_case` over `cases_done`) should equal
`avg_case_s`. If it does, concurrency is 1 and the multiplication is valid. Concurrent
requests seen on the model endpoint (`vllm:num_requests_running` > 1) are parallel
searches *within* one case, not parallel cases.
**Never estimate a run's length from a `--limit N` smoke.** Its "avg task time per
case" is a per-case duration on the easiest N cases of a deterministic prefix; the full
set ran 32% slower (72.7s vs 55.2s) on FRAMES. Smokes validate wiring, not wall-clock.
Live headline, behaviour and failure composition in one pass:
```sql
SELECT count(*) AS cases,
sum(CASE WHEN json_get_bool(attributes,'assertions','answer_equivalent','value')
THEN 1 ELSE 0 END) AS passed,
sum(CASE WHEN json_get(attributes,'assertions','answer_equivalent') IS NULL
THEN 1 ELSE 0 END) AS unjudged,
avg(json_get_float(attributes,'scores','cited_map','value')) AS cited_map,
avg(json_get_int(attributes,'attributes','n_requests')) AS req_per_case,
avg(json_get_int(attributes,'attributes','n_searches')) AS searches,
avg(json_get_int(attributes,'attributes','n_executions')) AS execs,
sum(json_get_int(attributes,'attributes','n_rejected_searches')) AS rejected,
sum(CASE WHEN json_get_str(attributes,'attributes','citation_status')='grounded'
THEN 1 ELSE 0 END) AS grounded
FROM records
WHERE service_name='evals' AND span_name='case: {case_name}'
AND start_timestamp > '<RUN_LAUNCH_TS>';
```
Why a case died, counted correctly:
```sql
SELECT sum(CASE WHEN exception_message LIKE '%token limit%' THEN 1 ELSE 0 END) AS token_limit,
sum(CASE WHEN exception_message NOT LIKE '%token limit%' THEN 1 ELSE 0 END) AS other,
count(*) AS dead_cases
FROM records
WHERE service_name='evals' AND is_exception
AND span_name='case: {case_name}'
AND start_timestamp > '<RUN_LAUNCH_TS>';
```
`ToolFailedError` is mostly **not** a defect — an exhausted search or code budget
reports failure to the model on purpose. `UnexpectedModelBehavior` is the one that
kills a case.
### The per-case diagnostic attributes
`attributes->'attributes'` on a case span carries what the capability actually did:
`n_requests`, `n_searches`, `n_search_calls`, `n_rejected_searches`, `n_failed_tools`,
`n_executions`, `cited_uris`, `cited_chunk_ids`, `searched_uris`, `citation_status`
(`grounded` | `missing` | `ungrounded`). `attributes->'metrics'` carries `requests`,
`input_tokens`, `output_tokens` for the case.
Cite rate comes from `citation_status`, not from `cited_map` — they answer different
questions, and conflating them has produced wrong claims before. And never steer on
raw cite rate: it is confounded by task success, so measure it among *correct* answers.

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#!/usr/bin/env bash
# Query the Logfire API. Key is read from ~/.logfire-read-key and never echoed.
# usage: lf-query.sh "<SQL>" [min_timestamp]
set -uo pipefail
KEY_FILE="$HOME/.logfire-read-key"
[ -r "$KEY_FILE" ] || { echo "missing $KEY_FILE"; exit 2; }
SQL="${1:?need SQL}"
MIN="${2:-$(date -u -v-2d +%Y-%m-%dT%H:%M:%SZ 2>/dev/null || date -u -d '2 days ago' +%Y-%m-%dT%H:%M:%SZ)}"
python3 - "$SQL" "$MIN" <<'PY'
import json, os, sys, urllib.request, urllib.error
sql, min_ts = sys.argv[1], sys.argv[2]
key = open(os.path.expanduser("~/.logfire-read-key")).read().strip()
# region comes from the key prefix: pylf_v2_<region>_...
parts = key.split("_")
region = parts[2] if len(parts) > 3 and parts[0] == "pylf" else "eu"
req = urllib.request.Request(
f"https://logfire-{region}.pydantic.dev/v2/query",
data=json.dumps({"sql": sql, "min_timestamp": min_ts}).encode(),
headers={"Authorization": f"Bearer {key}", "Content-Type": "application/json"},
)
try:
print(json.dumps(json.load(urllib.request.urlopen(req, timeout=120)), indent=2)[:6000])
except urllib.error.HTTPError as e:
print(f"HTTP {e.code}: {e.read().decode()[:600]}")
PY