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 skills/guillermoscript/lms-front/chatgpt-app-buildernpx skills add guillermoscript/lms-front --skill chatgpt-app-buildergit clone --depth 1 https://github.com/guillermoscript/lms-frontWrote 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/guillermoscript/lms-front/chatgpt-app-builder)<a href="https://agentmods.dev/skills/guillermoscript/lms-front/chatgpt-app-builder"><img src="https://agentmods.dev/badge/skills/guillermoscript/lms-front/chatgpt-app-builder.svg" alt="Measured on agentmods" 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 | $0.00055 | $0.00774 |
| Opus 5 | $0.00028 | $0.00387 |
| Sonnet 5 | $0.00011 | $0.00155 |
| Haiku 4.5 | $0.00006 | $0.00077 |
Grade A, and why
chatgpt-app-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 yesterday.
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 — 44 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Build with mcp-use
Treat the installed mcp-use package, its exported types, generated declarations, and the project's existing code as the source of truth. Inspect the installed version before choosing APIs or changing code.
Workflow
- Inspect
package.json, the server entry, exported tool refs,mcp-env.d.ts,views/,skills/, and the installedmcp-useversion. - Scaffold a new stable project with
create-mcp-use-app@latestand the appropriate template. Match the package version or dist-tag when working on beta, canary, or an existing versioned project. - Read only the references needed for the task:
- Server for tools, resources, prompts, MCP middleware, request context, and result envelopes.
- Views for interactive MCP Apps, React hooks, model context, host capabilities, assets, and CSP.
- Authentication for OAuth providers, verified identity, scopes, permissions, and authorization.
- Skills over MCP when a server should ship reusable workflows alongside its tools.
- Advanced features for OpenAPI, proxying, notifications, subscriptions, and elicitation.
- Migration only when retired or compatibility-only imports, helpers, registration shapes, UI patterns, or session assumptions are present.
- Verification before reporting implementation work complete.
- Implement against installed types. Prefer the framework's current conventions over copied examples or historical changelogs.
- Validate the smallest real lifecycle that proves the changed behavior, then expand checks in proportion to risk.
Core invariants
- Import server APIs from
mcp-use, React APIs frommcp-use/react, and OAuth provider adapters from theirmcp-use/oauth/*subpaths. - Define tool arguments with
inputSchema. AddoutputSchemafor structured results and every View-bound tool. - Return raw MCP result envelopes. A successful schema-backed tool must include matching
structuredContent; an expected failure may returnisError: truewith model-readablecontent. - Put each View at
views/<name>/view.tsxand bind it withview: { name: "<name>" }. - Export every statically declared tool ref consumed by a View. Default-export the server entry used by
mcp-use dev,build, andstart. - Keep identity and mutable workflow state request-scoped or in an external store. Treat client-reported metadata as unverified.
- Consider Skills over MCP when a server exposes a repeatable, multi-step workflow that would otherwise inflate tool descriptions.
What ships with it
8 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.
- yesterday Changed · +12 lines · +33 tokens per session a1064a58634a
- 5d ago First seen · 32 lines · 22 tokens per session scan A 99720bc364f7
chatgpt-app-builder is a skill published in the GitHub repository guillermoscript/lms-front (25 stars, last pushed 2d ago), licensed MIT. It adds 55 tokens to every session and 774 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 2026-08-30.
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