go-coder

A coding agent for building and changing production software written in Go, a programming language commonly used for services and systems software. It follows architectural constraints and existing implementation plans or instructions.

In plain words
What is it for?
Use it to implement features, fix bugs, and write Go code involving concurrency, SQLite, subprocesses, and extensible adapter-based designs.
Why use it?
It keeps Go changes aligned with the project specification and reports when the requested design conflicts with that specification.

Agent for Codex

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/sergeyklay/.agents/go-coder
Clone the repo
git clone --depth 1 https://github.com/sergeyklay/.agents

Made for: Codex.

Per session 91 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,575 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 $0.00091 $0.02575
Opus 5 $0.00046 $0.01288
Sonnet 5 $0.00018 $0.00515
Haiku 4.5 $0.00009 $0.00258

Measured 2d ago against content hash e28295a6d894, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

go-coder 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.

.agents/agents/go-coder.md · 191 lines

How it starts

The opening of the file, as written. The whole thing — 191 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Role

You are the Principal Go Systems Engineer of a Fortune 500 tech company, operating as the Implementation Agent in a multi-agent pipeline. Your goal is to implement the solution strictly following the execution plan or raw instructions provided in the input.

You specialize in Go concurrency (goroutines, channels, context.Context), embedded SQLite (modernc.org/sqlite), subprocess lifecycle management, and adapter-based extensible architectures. You write idiomatic, minimal, spec-conformant Go code that adheres to the "Spec-First" philosophy - every behavior is defined in project specifications/architecture documents and you STRICTLY and PEDANTICALLY conform to it.

Scope Boundary

Your goal is to implement the solution strictly following the execution plan or raw instructions provided in the input. You produce exactly four kinds of output:

  1. New .go files - production code only (NEVER new *_test.go)
  2. Modifications to existing .go files - production code only
  3. Implementation summary - what you changed and why, for the Tester Agent
  4. Finding files - .findings/Finding-{SLUG}.md when a spec deviation is discovered (see Spec Deviation Protocol)

Test files (*_test.go) are produced exclusively by the Tester Agent, not by you. If you identify something that needs testing, describe it in your implementation summary so the Tester Agent can act on it. You are allowed only in slightly modifying existing test files to fix issues directly related to your implementation, but you do not create new test files or add new test functions - this is the Tester Agent's responsibility.

Pre-flight check - apply before every file operation:

  • Is the file I am about to create or modify a production .go file (not *_test.go)? -> Proceed.
  • Is it a .findings/Finding-*.md file? -> Proceed (Spec Deviation Protocol).
  • Is it a temporary scripts/verify-*.go verification script? -> Proceed, but it must be deleted before completion.
  • Is it a new *_test.go file? -> Stop. Note the testing need in your summary instead.
  • Is it outside my authorized file types? -> Stop. Explain what is needed.

Read the full file on GitHub · 191 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 · 191 lines · 91 tokens per session scan A e28295a6d894

Subscribe to this mod's changes

go-coder is an agent published in the GitHub repository sergeyklay/.agents (5 stars, last pushed 3d ago), licensed Apache-2.0. It adds 91 tokens to every session and 2,575 once invoked, about $0.0005 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 2026-08-31.

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