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 agentmods add skills/existential-birds/beagle/deepagents-code-reviewnpx skills add existential-birds/beagle --skill deepagents-code-reviewgit clone --depth 1 https://github.com/existential-birds/beagleWhat 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 | $0.00053 | $0.03337 |
| Opus 5 | $0.00026 | $0.01669 |
| Sonnet 5 | $0.00011 | $0.00667 |
| Haiku 4.5 | $0.00005 | $0.00334 |
Grade A, and why
deepagents-code-review 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.
How it starts
The opening of the file, as written. The whole thing — 488 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Deep Agents Code Review
When reviewing Deep Agents code, check for these categories of issues.
Anti-confabulation (gate 0 — runs before every other gate)
Before issuing any finding — flag a bug, anti-pattern, or improvement — you MUST echo the exact artifact you are judging, quoted from a source you read in this turn:
- The code finding: its
file:lineplus the cited code, read freshly now. - The agent code under review: the
create_deep_agent, backend, subagent, or middleware snippet your finding depends on, quoted from the file you just read.
The artifact is the only source of truth. Never infer what you are reviewing from the branch name, the working directory, surrounding files, or recollection. If your mental model differs from the freshly read source, the source wins. A finding issued without a same-turn echo of its target is invalid — emit the echo first, or do not emit the finding.
This gate exists because an LLM under contextual priming will confidently flag code that is not in the file. It runs before the gates below.
Review gates (evidence-bound)
Run these steps in order before and while you write findings. Skipping a step is a failed review.
- Locate — Enumerate call sites in scope (
create_deep_agent,CompiledSubAgent,CompositeBackend, custombackend=,interrupt_on,checkpointer,store). Pass: You list each relevant file path and line number (or a grep/search result that proves where the code lives). - Anchor — For each suspected issue, tie it to quoted or line-referenced code from those files, not to imports or names alone. Pass: Every finding includes evidence (
path:lineplus a short quote or “absent parameter” note showing the gap). - Classify — Map each anchored issue to one category below (Critical → Performance) and a severity. Pass: The category label matches what the cited code actually does or omits.
- Runtime claims — If you say something will error, fail at runtime, or leak data, Pass: The cited snippet shows the exact API combo (e.g.
interrupt_onset with nocheckpointerin the same construction path), or you state uncertain and what would confirm it.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 2d ago First seen · 488 lines · 53 tokens per session scan A 286792580da4
deepagents-code-review is a skill published in the GitHub repository existential-birds/beagle (79 stars, last pushed 23d ago), licensed Apache-2.0. It adds 53 tokens to every session and 3,337 once invoked, about $0.0003 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.
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