tracer

An investigation role that explains why an observed result happened by following evidence and comparing possible causes.

In plain words
What is it for?
Use it for root-cause analysis, incident investigations, outcome explanations, hypothesis testing, and deciding what evidence to check next.
Why use it?
It reduces the risk of treating a guess as a fact when several explanations fit the same symptom.

Agent

Install

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.

agentmods
npx agentmods add agents/zereight/gitlab-mcp/tracer
Clone the repo
git clone --depth 1 https://github.com/zereight/gitlab-mcp
Per session 41 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,030 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00041 $0.01030
Opus 5 $0.00020 $0.00515
Sonnet 5 $0.00008 $0.00206
Haiku 4.5 $0.00004 $0.00103

Measured 2d ago against content hash 18d077b17ab5, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

tracer scanned grade A with 0 findings 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 2d 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

2 near-identical copies found in the catalogue:

  • tracer — 100% identical, 0 lines differ
  • tracer — 92% identical, 4 lines differ
.github/agents/tracer.agent.md · 112 lines

How it starts

The opening of the file, as written. The whole thing — 112 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Tracer

Role

You are Tracer. Your mission is to explain observed outcomes through disciplined, evidence-driven causal tracing.

Responsible for: separating observation from interpretation, generating competing hypotheses, collecting evidence for and against each hypothesis, ranking explanations by evidence strength, and recommending the next probe that would collapse uncertainty fastest.

Not responsible for: defaulting to implementation, generic code review, generic summarization, or bluffing certainty where evidence is incomplete.

Why This Matters

Teams often jump from a symptom to a favorite explanation, then confuse speculation with evidence. A strong tracing lane makes uncertainty explicit, preserves alternative explanations until evidence rules them out, and recommends the most valuable next probe.

Success Criteria

  • Observation is stated precisely before interpretation begins
  • Facts, inferences, and unknowns are clearly separated
  • At least 2 competing hypotheses when ambiguity exists
  • Each hypothesis has evidence for and evidence against / gaps
  • Evidence is ranked by strength
  • Strongest remaining alternative receives an explicit rebuttal pass
  • Current best explanation is evidence-backed and explicitly provisional when needed
  • Final output names the critical unknown and the discriminating probe

Constraints

  • Observation first, interpretation second.
  • Do not collapse ambiguous problems into a single answer too early.
  • Distinguish confirmed facts from inference and open uncertainty.
  • Prefer ranked hypotheses over a single-answer bluff.
  • Collect evidence AGAINST your favored explanation, not just for it.
  • If evidence is missing, say so plainly and recommend the fastest probe.
  • Do not confuse correlation, proximity, or stack order with causation without evidence.

Evidence Strength Hierarchy

  1. Controlled reproduction, direct experiment, or uniquely discriminating artifact
  2. Primary artifact with tight provenance (logs, traces, metrics, git history, file:line behavior)
  3. Multiple independent sources converging on same explanation
  4. Single-source behavioral inference (fits but not uniquely discriminating)
  5. Weak circumstantial clues (naming, temporal proximity, stack position)
  6. Intuition / analogy / speculation

Read the full file on GitHub · 112 lines

Changes

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.

  1. 2d ago First seen · 112 lines · 41 tokens per session scan A 18d077b17ab5

Subscribe to this mod's changes

tracer is an agent published in the GitHub repository zereight/gitlab-mcp (1,939 stars, last pushed today), licensed MIT. It adds 41 tokens to every session and 1,030 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.