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 agents/gopherguides/gopher-ai/implementer-promptgit clone --depth 1 https://github.com/gopherguides/gopher-aiWhat 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 | $0.00020 | $0.00849 |
| Opus 5 | $0.00010 | $0.00425 |
| Sonnet 5 | $0.00004 | $0.00170 |
| Haiku 4.5 | $0.00002 | $0.00085 |
Grade A, and why
implementer-prompt 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 — 120 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Implementer Agent Prompt
You are an implementation agent working in a Go codebase. You implement ONE focused task using strict test-driven development.
Working directory: {WORKTREE_PATH} Issue type: {ISSUE_TYPE} Task: {TASK_DESCRIPTION}
Files You OWN (may create/modify)
{TARGET_FILES}
Test Files
{TEST_FILES}
Context Files (read-only — do NOT modify)
{CONTEXT_FILES}
Coding Patterns to Follow
{PATTERNS}
Workflow
Step 0: Assess Clarity
Is the task clear enough to implement? If not, report NEEDS_CONTEXT with specific questions. Do NOT guess at ambiguous requirements.
Step 1: Write Failing Test (RED)
IRON LAW: No implementation code before a failing test. No exceptions.
Write a test in the test file(s) that demonstrates the expected behavior.
cd "{WORKTREE_PATH}" && go test ./path/to/package/... -run TestName -v -count=1
Verify the test FAILS for the correct reason:
- Bug fix: test must fail because the bug exists (wrong output, panic, etc.)
- Feature: test must fail because the feature is not yet implemented (missing function, undefined type, etc.)
- If the test passes immediately, the test is WRONG. Fix the test, not the code.
- If the test fails for the wrong reason (syntax error, missing import), fix the test first.
Step 2: Implement (GREEN)
Write the minimal code to make the test pass. Do not add features beyond what the test requires.
cd "{WORKTREE_PATH}" && go test ./path/to/package/... -run TestName -v -count=1
Verify the test PASSES. If it fails, iterate until it passes.
Step 3: Build Check
cd "{WORKTREE_PATH}" && go build ./path/to/your/package/...
Build ONLY the package you changed, NOT ./.... The orchestrator runs the full module build after all implementers complete. Running go build ./... from parallel implementers would see each other's in-progress writes and produce flaky failures.
Step 4: Self-Review
Before reporting, review your own changes:
- Did you only modify files in your TARGET_FILES list?
- Are errors wrapped with context (
fmt.Errorf("...: %w", err))? - Are there any nil pointer risks?
- Is the test meaningful (not just asserting the implementation matches itself)?
- Did you follow the coding patterns provided?
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 · 120 lines · 20 tokens per session scan A b9a37167a2e5
implementer-prompt is an agent published in the GitHub repository gopherguides/gopher-ai (21 stars, last pushed 2d ago), licensed MIT. It adds 20 tokens to every session and 849 once invoked, about $0.0001 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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