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 saajunaid/caddis-plugin --skill backend-to-frontend-handoffgit clone --depth 1 https://github.com/saajunaid/caddis-pluginWrote 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/saajunaid/caddis-plugin/backend-to-frontend-handoff)<a href="https://agentmods.dev/skills/saajunaid/caddis-plugin/backend-to-frontend-handoff"><img src="https://agentmods.dev/badge/skills/saajunaid/caddis-plugin/backend-to-frontend-handoff/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/saajunaid/caddis-plugin/backend-to-frontend-handoff"><img src="https://agentmods.dev/badge/skills/saajunaid/caddis-plugin/backend-to-frontend-handoff.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 | $0.01337 |
| Opus 5.5 | $0.00017 | $0.00535 |
| Sonnet 5.5 | $0.00008 | $0.00267 |
| Haiku 4.5 | $0.00004 | $0.00134 |
Grade A, and why
backend-to-frontend-handoff-docs 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 17d 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 — 140 lines — stays where its author put it; the contents beside it link to each section on GitHub.
API Handoff Mode
No Chat Output: Produce the handoff document only. No discussion, no explanation—just the markdown block saved to the handoff file.
You are a backend developer completing API work. Your task is to produce a structured handoff document that gives frontend developers (or their AI agents) full business and technical context to build integration/UI without needing to ask backend questions.
Works with: Any AI coding agent (Claude, Cursor, GitHub Copilot, Windsurf, etc.)
When to use: After completing backend API work—endpoints, DTOs, validation, business logic—run this mode to generate handoff documentation.
Simple API shortcut: If the API is straightforward (CRUD, no complex business logic, obvious validation), skip the full template—just provide the endpoint, method, and example request/response JSON. Frontend can infer the rest.
Goal
Produce a copy-paste-ready handoff document with all context a frontend AI agent needs to build UI/integration correctly and confidently.
File Location Conventions
Choose the appropriate location based on your agent setup:
| Agent | Handoff File Location |
|---|---|
| Claude | .claude/docs/ai/<feature-name>/api-handoff.md |
| Cursor | .cursor/docs/<feature-name>/api-handoff.md |
| GitHub Copilot | .github/docs/<feature-name>/api-handoff.md |
| Windsurf | .windsurf/docs/<feature-name>/api-handoff.md |
| Generic | docs/api-handoff/<feature-name>.md |
Use whichever location matches your project's agent documentation structure.
Inputs
- Completed API code (endpoints, controllers, services, DTOs, validation).
- Related business context from the task/user story.
- Any constraints, edge cases, or gotchas discovered during implementation.
Workflow
- Collect context — confirm feature name, relevant endpoints, DTOs, auth rules, and edge cases.
- Create/update handoff file — write the document to the appropriate location (see table above). Increment the iteration suffix (
-v2,-v3, …) if rerunning after feedback. - Paste template — fill every section below with concrete data. Omit subsections only when truly not applicable (note why).
- Double-check — ensure payloads match actual API behavior, auth scopes are accurate, and enums/validation reflect backend logic.
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.
- 17d ago Changed · -13 tokens per session ca8d47c81ae4
- 1mo ago First seen · 140 lines · 55 tokens per session scan A a28a194ee538
backend-to-frontend-handoff-docs is a skill published in the GitHub repository saajunaid/caddis-plugin (0 stars, last pushed today), licensed MIT. It adds 42 tokens to every session and 1,337 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 2026-09-03.
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