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activity-builder

activity-builder is a skill for Claude Code, Codex from uselessspace/freedeepagents-activity-builder. It costs 51 tokens per session (1,389 once invoked), scanned A, original, MIT.

An implementation workflow for building an FDA activity after its brief and classification are complete.

In plain words
What is it for?
Use it to scaffold and fill backend files, add image handling, build a static preview, support uploads or transcripts, and apply the required capability and asset rules.
Why use it?
It keeps activity-specific business logic and optional frontend or image work in the activity itself instead of putting it into shared runtime code.

Skill for Claude CodeCodex

Part of the freedeepagents-activity-builder plugin — 13 skills shipped together

not rated 2 16d ago A scan 51 tokens original MIT
View the source file uselessspace/freedeepagents-activity-builder
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 skills/uselessspace/freedeepagents-activity-builder/activity-builder
Any agent
npx skills add uselessspace/freedeepagents-activity-builder --skill activity-builder
Clone the repo
git clone --depth 1 https://github.com/uselessspace/freedeepagents-activity-builder

Made for: Claude Code, Codex.

Or install freedeepagents-activity-builder, the plugin that ships this one along with the rest of its 13 skills.

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.

agentmods badge for activity-builder

README.md
[![agentmods](https://agentmods.dev/badge/skills/uselessspace/freedeepagents-activity-builder/activity-builder.svg)](https://agentmods.dev/skills/uselessspace/freedeepagents-activity-builder/activity-builder)
Your own site
<a href="https://agentmods.dev/skills/uselessspace/freedeepagents-activity-builder/activity-builder"><img src="https://agentmods.dev/badge/skills/uselessspace/freedeepagents-activity-builder/activity-builder.svg" alt="Measured on agentmods" height="20"></a>
Per session 51 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,389 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 $0.00051 $0.01389
Opus 5 $0.00026 $0.00694
Sonnet 5 $0.00010 $0.00278
Haiku 4.5 $0.00005 $0.00139

Measured 4d ago against content hash 1266f3961592, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

activity-builder 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 4d 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.

skills/activity-builder/SKILL.md · 121 lines

How it starts

The opening of the file, as written. The whole thing — 121 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Activity Builder

何时用：Brief + Classification 都齐、要真正写文件时。Static Preview 前端完成后或 Card-only 实现完成后，都先交 /activity-review。

Own scaffold and implementation. Require both Activity Brief and Activity Classification before changing files.

Shared References

Use the package assets relative to this skill:

  • ../../workflows/02-author-backend.md for backend scaffold and host skill.
  • ../../workflows/03-image-tooling.md when image_axis is not none.
  • ../../workflows/04-derive-frontend.md when frontend_axis is static-preview.
  • ../../references/user-upload.md for end-user uploads; ../../references/preview-agent-turns.md for structured SPA actions needing model understanding, Skills, planning, or multiple tools.
  • ../../references/preview-asr.md when the SPA needs a transcript immediately without creating an Agent turn; use upload + attachment_refs when the Agent must own the recording instead.
  • ../../policies/capabilities.md plus the capability-specific reference for every value in Classification runtime_capabilities.
  • ../../references/asset-lifecycle.md for replace/delete/durability semantics.
  • ../../references/preview-navigation.md for agent-to-preview.
  • ../../references/handler-context-lifecycle.md before work may outlive a tool/handler call.
  • ../../workflows/06-verify-directory.md for verification expectations.
  • ../../workflows/07-migrate-existing.md when the user wants to fork an existing activity.
  • ../../references/card-block-types.md — read before writing cards; it owns the 6 block schemas, form semantics, and form-vs-action decision.
  • ../../references/card-system-tools.md for the canonical card_emit_template / artifact_emit / memory_add tool signatures and a worked example.
  • ../../policies/output-protocol.md for the card-system transport contract.
  • ../../policies/manifest-allowed-fields.md for manifest field whitelist.
  • ../../policies/runtime-boundary.md and ../../policies/skill-layering.md for hard boundaries.
  • ../../references/store-mode-table.md for persistent image URLs.
  • ../../references/data-mode-selection.md for SQLite/typed-KV/hybrid/none.
  • ../../references/sqlite-storage.md whenever Classification enables SQLite.

Read the full file on GitHub · 121 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. 4d ago First seen · 121 lines · 51 tokens per session scan A 1266f3961592

Subscribe to this mod's changes

activity-builder is a skill published in the GitHub repository uselessspace/freedeepagents-activity-builder (2 stars, last pushed 16d ago), licensed MIT. It adds 51 tokens to every session and 1,389 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 2026-08-31.

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