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 skills add gaelic-ghost/socket --skill build-acp-agentgit clone --depth 1 https://github.com/gaelic-ghost/socketWrote 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/skills/gaelic-ghost/socket/build-acp-agent)<a href="https://agentmods.dev/skills/gaelic-ghost/socket/build-acp-agent"><img src="https://agentmods.dev/badge/skills/gaelic-ghost/socket/build-acp-agent/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/skills/gaelic-ghost/socket/build-acp-agent"><img src="https://agentmods.dev/badge/skills/gaelic-ghost/socket/build-acp-agent.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 | $0.00042 | $0.00864 |
| Opus 5.5 | $0.00017 | $0.00346 |
| Sonnet 5.5 | $0.00008 | $0.00173 |
| Haiku 4.5 | $0.00004 | $0.00086 |
Grade A, and why
build-acp-agent 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 — 87 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Build ACP Agent
Build the agent process that an ACP client launches. Do not build an editor
plug-in or MCP server when the requirement is an editor-native coding agent.
Read references/acp-implementation-map.md before selecting an SDK or registry
distribution.
Implementation Workflow
- Define concrete client targets and the user-visible behavior they require.
- Use ACP v1, the current latest protocol, and an official SDK when its language and runtime fit. Treat v2 and non-completed RFDs as experimental; do not ship them as the portable baseline. Use raw JSON-RPC only when an SDK cannot support a required platform or feature.
- Implement initialization first:
- negotiate
protocolVersion - advertise only implemented agent capabilities
- inspect client filesystem and terminal capabilities before using them
- advertise real authentication methods and implementation information
- negotiate
- Implement the required session baseline: new, prompt, cancel, and update.
- Add optional load, resume, fork, list, close, modes, configuration, plans,
slash commands, rich prompt content, or MCP transports only with matching
capability declarations and tests. Keep draft
session/delete, logout, elicitation, additional directories, and remote transports behind explicit experimental flags and interoperability tests. - Render tool calls, diffs, terminals, plans, and streamed content in the ACP structures the target clients understand.
- Route dangerous operations through permission requests and fail closed when approval transport fails or times out.
- Keep stdout exclusively for ACP JSON-RPC. Send logs and diagnostics to stderr without leaking credentials or prompt content unnecessarily.
- Bind every session to its client-provided cwd and any negotiated additional roots. Isolate cancellation, model choice, history, and mutable state by session.
- Test initialization, authentication, session lifecycle, streaming, cancellation, permissions, invalid messages, process shutdown, and each advertised optional capability against representative clients.
What ships with it
2 files 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.
- 1mo ago First seen · 87 lines · 42 tokens per session scan A 847f28bff3c3
build-acp-agent is a skill published in the GitHub repository gaelic-ghost/socket (7 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 42 tokens to every session and 864 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 skills, from other repositories
data-engineering
Builds and operates data pipelines — ingestion, transformation, orchestration, quality testing, and reliability of data delivery. Use this to design or debug a pipeline, decide batch versus streaming, add data quality checks, handle late or duplicate data, or work out why a dashboard's numbers changed without anyone…
api-design
Designs interfaces that survive their consumers — resource modeling, errors, versioning, pagination, and compatibility. Use this to design a new API, review one before it ships, decide how to version or deprecate, fix an interface consumers keep misusing, or work out whether a change is breaking.
architecture
Proactive architecture review — explore codebase structure, generate a self-contained HTML report with Mermaid diagrams and candidate improvements, then grill the findings. Use when planning a large refactor, onboarding to an unfamiliar codebase, or before a major architectural change.
api-design-document
Design a production-ready API specification aligned with OpenAPI 3.1 standards. Covers resource modeling, endpoint design, request/response contracts, authentication, versioning strategy, error handling, rate limiting, and pagination. Use when designing a new REST, GraphQL, or event-driven API.
contracts
Team baseline for external-interface contract artifacts: OpenAPI, JSON Schema, AsyncAPI, .proto, and GraphQL SDL, with spectral, ajv, buf, and graphql-inspector validation. Nudges devs toward contract-first artifacts; never writes them and never scaffolds a contracts/ directory. Auto-triggers for what contract should…
craft
Use when a product idea is still vague and needs to become a clear definition of what to build — "let's craft an app like X", "help me define what I actually want", "clarify this idea before we plan it". Also use before planning or implementation when requirements, UX, domain behaviour, or technical preferences have…