Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add comet-ml/opik-skills --skill opik-comparegit clone --depth 1 https://github.com/comet-ml/opik-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/comet-ml/opik-skills/opik-compare)<a href="https://agentmods.dev/skills/comet-ml/opik-skills/opik-compare"><img src="https://agentmods.dev/badge/skills/comet-ml/opik-skills/opik-compare/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/comet-ml/opik-skills/opik-compare"><img src="https://agentmods.dev/badge/skills/comet-ml/opik-skills/opik-compare.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00156 | $0.03401 |
| Opus 5.5 | $0.00062 | $0.01360 |
| Sonnet 5 | $0.00031 | $0.00680 |
| Haiku 4.5 | $0.00016 | $0.00340 |
Grade A, and why
opik-compare scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
import json, urllib.parse This is a copy
98% identical to opik-compare — 33 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 174 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Compare — Candidate vs Baseline Over a Suite
Definition of done: two experiments on the same suite — a baseline and a candidate — read back item by item, with the per-metric deltas, the cases that went pass → fail (regressions) and fail → pass (fixes), the worst rows, a note on whether the runs are comparable, and the Opik compare-view link. If only one run exists, the done state is "baseline created — rerun after the change". If the suite can't be run or read, stop at the first genuine blocker and return exactly one next step. Aggregate scores alone are not a comparison; a verdict is not this skill's job.
Operate: run the candidate the same way the baseline was run, read both back from Opik rather than from the run's console output, name the specific cases that changed — and change no application code. The only file this skill writes is a throwaway runner outside the repo.
Inputs
The entry point is /opik-compare <suite> (run the suite now as the candidate, compare against the latest prior run), /opik-compare <experiment-A> <experiment-B> (read two existing runs, no new run), or /opik-compare right after /opik-test (that suite). Infer the rest; treat these as optional overrides:
- suite (default:
<project>-regressions, or the one/opik-testjust wrote to) · baseline (default: the most recent earlier experiment on the suite) · candidate name (default:candidate-<short git sha>) · judge model for assertions (default: the suite's / the baseline's) · runs per item (default: the suite's policy).
Ask only at a genuine, non-inferable blocker (see Blockers).
Activation — the only in-scope work
1. Resolve the suite and the baseline
import opik
client = opik.Opik()
suite = client.get_test_suite(name="<suite>", project_name="<project>")
prior = client.get_test_suite_experiments(name="<suite>", project_name="<project>") # newest first is not guaranteed — sort by created_at yourself
Baseline = the most recent prior experiment on this suite, unless the user names one. No prior experiment → this run is the baseline (step 3 still runs; status baseline_created). Two explicit experiments → skip step 3, go to step 4.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 4d ago First seen · 174 lines · 156 tokens per session scan A 0dbe6d16e887
opik-compare is a skill published in the GitHub repository comet-ml/opik-skills (8 stars, last pushed yesterday), licensed Apache-2.0. It adds 156 tokens to every session and 3,401 once invoked, about $0.0006 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). It is 98% identical to opik-compare, differing in 33 lines, and is treated as a copy.
Other skills, from other repositories
opik-compare
Run a candidate against the baseline over an Opik test suite and read the numbers back — which cases broke, which got fixed, the per-metric deltas, worst rows, and whether the two runs are comparable — with the Opik compare-view link. Runs via the SDK; reads results via the MCP when connected. Does not issue a…
opik-verify
Decide ship or hold for a candidate from the compare skill's numbers, against an explicit release policy — regressions, pass rate, safety-tagged cases, subgroup consistency, latency and cost budgets, flakiness, evidence size, and whether the judge is validated. Reads two experiments on an Opik test suite via the SDK…
opik-test
Turn a failing Opik trace (or a described failure) into a repeatable regression check — a test-suite item with the trace's input and one or two binary assertions — so a fix can be verified by the compare skill. Works over the SDK; uses the MCP write tool when connected. Returns the suite, the item, and the assertion.…
opik-diagnose
Surface the Opik traces worth a developer's attention, ranked by signal — Diagnostics issues first, then errors, failed tool calls, latency, regressions, and low online-eval scores. With the Opik MCP connected it lists the project's agentinsightsissue entities, offers to turn Diagnostics on when the project has it…
opik-evaluate
Build an LLM evaluation and run it against the app, returning an Opik experiment with scores and its link. Picks a test suite with judge assertions or a dataset with metrics, sources cases from traces or synthetic data, scores heuristics-first then one-failure-mode judges, runs client-side via the SDK or server-side…
opik-instrument
Add Opik tracing to an existing app and verify a real trace lands. Installs the Opik package, detects the language and LLM framework, adds the minimum tracing, runs a safe representative path, confirms a trace in Opik, and returns the trace link. Use for "instrument my code", "add opik tracing", "add observability"…