A specialist coding agent for writing tests with the Opus model. It is intended for cases where another test-writing agent misses edge cases or struggles with complex test setup.

Use it to inspect existing fixtures and source code, write unittest tests, reuse test fakes, and run the project's specified test commands.

It provides a separate path for difficult tests, including tests with subtle behavior or security-sensitive code.

How dancing-bear-show/dancing-bear configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to dancing-bear-show/dancing-bear. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/dancing-bear-show/dancing-bear/main/.claude/agents/tester-opus.md

Clone the repo

git clone --depth 1 https://github.com/dancing-bear-show/dancing-bear

Made for: Claude Code.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/agents/dancing-bear-show/dancing-bear/tester-opus/github.svg)](https://agentmods.dev/agents/dancing-bear-show/dancing-bear/tester-opus)

Your own site

<a href="https://agentmods.dev/agents/dancing-bear-show/dancing-bear/tester-opus"><img src="https://agentmods.dev/badge/agents/dancing-bear-show/dancing-bear/tester-opus/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.

Your own site · 80×15

<a href="https://agentmods.dev/agents/dancing-bear-show/dancing-bear/tester-opus"><img src="https://agentmods.dev/badge/agents/dancing-bear-show/dancing-bear/tester-opus.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 42 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 374 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00042	$0.00374
Opus 5.5	$0.00017	$0.00150
Sonnet 5.5	$0.00008	$0.00075
Haiku 4.5	$0.00004	$0.00037

Measured yesterday against content hash 44af384a6160, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

tester-opus 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 yesterday.

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.

.claude/agents/tester-opus.md · 39 lines

What it actually says

Test Writing Agent (Opus)

You are a test specialist for dancing-bear. Use this agent when Sonnet-based tester has struggled: complex mock setups, subtle behavioral edge cases, or tests for security-critical paths.

Before Writing Tests

Read tests/fixtures.py and tests/fakes/ for existing helpers
Read the source module to understand what to test

Test Patterns

Framework: unittest (not pytest)
Use fakes/stubs from tests/fakes/ — never construct real API response dicts manually
Patch where the name is used, not where it's defined
Specific assertions: assertEqual, assertIn, assertIsInstance
Never run tests that require network/secrets without explicit approval

After Writing Tests

PYTHONPATH="$PWD/src" python3 -m unittest discover -s tests/<domain>_tests/ -t . -v
make test

Never a bare unittest run — in a worktree an inherited PYTHONPATH resolves imports to the main checkout, so tests pass against unmodified code.

Review Concerns (Self-Check Before Finishing)

concerns/tests.md, concerns/reuse.md, concerns/collateral-damage.md (when testing a fix — cover every input form and entry point reaching the guard, not just the reported case; see incomplete-guard-coverage)

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.

yesterday First seen · 39 lines · 42 tokens per session scan A 44af384a6160

Subscribe to this mod's changes

tester-opus is an agent published in the GitHub repository dancing-bear-show/dancing-bear (7 stars, last pushed yesterday), licensed MIT. It adds 42 tokens to every session and 374 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 2026-11-07.

Testing automation calendar cli gmail oauth2 outlook

tester-opus next to 6 agents from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
tester-opusdancing-bear-show/dancing-bear	Agent	7	yesterday	MIT	A	42	Claude Code
docs-specialistZaxbyHub/opencode-swarm	Agent	518	today	MIT	A	34	Claude Code
atomic-auditordamusix/atomic-claude	Agent	116	6d ago	MIT	A	169	Claude Code
seo-meta-optimizerechoVic/blade-code	Agent	181	26d ago	MIT	A	39	Claude Code
scramjet:instruction-semantics-analyzerLeanAndMean/scramjet	Agent	8	5d ago	Apache-2.0	A	35	Claude Code
fe-reviewerEffulgent-Point/paw	Agent	2	2mo ago	MIT	A	27	Claude Code
build-agentfentas/cuite	Agent	2	8mo ago	none	A	8	Claude Code

dancing-bear: Agent for Claude Code