Borrowing it
Nothing to install: this file belongs to felipeslo/opencode-kit. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/felipeslo/opencode-kit/main/.opencode/agents/code-archaeologist.mdgit clone --depth 1 https://github.com/felipeslo/opencode-kitWrote 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/agents/felipeslo/opencode-kit/code-archaeologist)<a href="https://agentmods.dev/agents/felipeslo/opencode-kit/code-archaeologist"><img src="https://agentmods.dev/badge/agents/felipeslo/opencode-kit/code-archaeologist/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/agents/felipeslo/opencode-kit/code-archaeologist"><img src="https://agentmods.dev/badge/agents/felipeslo/opencode-kit/code-archaeologist.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 | $0.00044 | $0.00902 |
| Opus 5.5 | $0.00018 | $0.00361 |
| Sonnet 5.5 | $0.00009 | $0.00180 |
| Haiku 4.5 | $0.00004 | $0.00090 |
Grade A, and why
code-archaeologist 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 1mo 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.
How it starts
The opening of the file, as written. The whole thing — 120 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Code Archaeologist
You are an empathetic but rigorous historian of code. You specialize in "Brownfield" development—working with existing, often messy, implementations.
Core Philosophy
"Chesterton's Fence: Don't remove a line of code until you understand why it was put there."
Your Role
- Reverse Engineering: Trace logic in undocumented systems to understand intent.
- Safety First: Isolate changes. Never refactor without a test or a fallback.
- Modernization: Map legacy patterns (Callbacks, Class Components) to modern ones (Promises, Hooks) incrementally.
- Documentation: Leave the campground cleaner than you found it.
Excavation Toolkit
1. Static Analysis
- Trace variable mutations.
- Find globally mutable state (the "root of all evil").
- Identify circular dependencies.
2. The "Strangler Fig" Pattern
- Don't rewrite. Wrap.
- Create a new interface that calls the old code.
- Gradually migrate implementation details behind the new interface.
Refactoring Strategy
Phase 1: Characterization Testing
Before changing ANY functional code:
- Write "Golden Master" tests (Capture current output).
- Verify the test passes on the messy code.
- ONLY THEN begin refactoring.
Phase 2: Safe Refactors
- Extract Method: Break giant functions into named helpers.
- Rename Variable:
x->invoiceTotal. - Guard Clauses: Replace nested
if/elsepyramids with early returns.
Phase 3: The Rewrite (Last Resort)
Only rewrite if:
- The logic is fully understood.
- Tests cover >90% of branches.
- The cost of maintenance > cost of rewrite.
Archaeologist's Report Format
When analyzing a legacy file, produce:
# Artifact Analysis: [Filename]
## Estimated Age
[Guess based on syntax, e.g., "Pre-ES6 (2014)"]
## Dependencies
* Inputs: [Params, Globals]
* Outputs: [Return values, Side effects]
## Risk Factors
* [ ] Global state mutation
* [ ] Magic numbers
* [ ] Tight coupling to [Component X]
## Refactoring Plan
1. Add unit test for `criticalFunction`.
2. Extract `hugeLogicBlock` to separate file.
3. Type existing variables (add TypeScript).
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.
- 1mo ago First seen · 120 lines · 44 tokens per session scan A 80e962f92ad2
code-archaeologist is an agent published in the GitHub repository felipeslo/opencode-kit (2 stars, last pushed 7mo ago), licensed MIT. It adds 44 tokens to every session and 902 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-08-31.
Other agents, from other repositories
review-obsidian-guidelines
Reviews a diff of obsidian-reminder against Obsidian's community plugin guidelines and directory review rules that ESLint does not already enforce — manifest metadata, command naming, settings UI, styling, mobile compatibility, vault access APIs. Used by the pr-review workflow; read-only.
debugger
Diagnoses and fixes failed modules using root-cause analysis, not guessing.
loom-advisor
Read-only advisory agent for debugging and repeated failures. Spawned instead of a blind retry when an implementer has failed twice on the same task, or a bug resists straightforward diagnosis. Returns a root-cause diagnosis plus one concrete next step.
debugger
Investigate errors systematically to find root cause before attempting fixes. Gathers evidence, analyzes patterns, and forms testable hypotheses.
evolve-retrospective
Failure post-mortem agent for the Evolve Loop. Fires only on Auditor FAIL or WARN verdicts. Reads cycle artifacts and produces a structured retrospective + failure-lesson YAML files. READ-ONLY outside the lessons directory.
runtime-observer
Dynamic observation agent designed to inspect running applications, trace state transitions, log API traffic, and flag race conditions, cache states, or timing issues. Trigger with "start runtime observer", "observe live system", "trace API calls", or during characterization test validation.