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debug:fastapi

debug:fastapi is a skill for Claude Code from SnakeO/claude-debug-and-refactor-skills-plugin. It costs 74 tokens per session (4,484 once invoked), scanned A, original, no licence file.

A troubleshooting guide for FastAPI, a Python framework for building web APIs.

In plain words
What is it for?
Diagnosing async and await problems, Pydantic validation errors such as HTTP 422 responses, dependency injection failures, CORS configuration issues, database session management, and circular imports.
Why use it?
It provides a structured four-phase way to investigate common API failures instead of debugging them ad hoc.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the debug-and-refactor plugin — 45 skills shipped together

not rated 9repo 9mo ago A scan 74 tokens no licence

Good fit Diagnosing async and await problems, Pydantic validation errors such as HTTP 422 responses, dependency injection failures, CORS configuration issues, database session management, and circular imports.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/snakeo/claude-debug-and-refactor-skills-plugin/debug-fastapi
View source ↗ SnakeO/claude-debug-and-refactor-skills-plugin
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.

Any agent
npx skills add SnakeO/claude-debug-and-refactor-skills-plugin --skill debug-fastapi
Clone the repo
git clone --depth 1 https://github.com/SnakeO/claude-debug-and-refactor-skills-plugin

Made for: Claude Code.

Or install debug-and-refactor, the plugin that ships this one along with the rest of its 45 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 debug:fastapi

README.md
[![agentmods](https://agentmods.dev/badge/skills/snakeo/claude-debug-and-refactor-skills-plugin/debug-fastapi/github.svg)](https://agentmods.dev/skills/snakeo/claude-debug-and-refactor-skills-plugin/debug-fastapi)
Your own site
<a href="https://agentmods.dev/skills/snakeo/claude-debug-and-refactor-skills-plugin/debug-fastapi"><img src="https://agentmods.dev/badge/skills/snakeo/claude-debug-and-refactor-skills-plugin/debug-fastapi/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.

agentmods 80×15 button for debug:fastapi

Your own site · 80×15
<a href="https://agentmods.dev/skills/snakeo/claude-debug-and-refactor-skills-plugin/debug-fastapi"><img src="https://agentmods.dev/badge/skills/snakeo/claude-debug-and-refactor-skills-plugin/debug-fastapi.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 74 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,484 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown 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 5.1 $0.00074 $0.04484
Opus 5.5 $0.00030 $0.01794
Sonnet 5.5 $0.00015 $0.00897
Haiku 4.5 $0.00007 $0.00448

Measured 2mo ago against content hash 71689ce794a7, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

debug:fastapi scanned grade A with 1 finding 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 2mo 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

# Use curl to reproduce
plugins/debug-and-refactor/skills/debug-fastapi/SKILL.md · 728 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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. 2mo ago First seen · 728 lines · 74 tokens per session scan A 71689ce794a7

Subscribe to this mod's changes

debug:fastapi is a skill published in the GitHub repository SnakeO/claude-debug-and-refactor-skills-plugin (9 stars, last pushed 9mo ago), with no licence file. It adds 74 tokens to every session and 4,484 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Backend and APIsDebugging
Related

debug:fastapi compared with skills from other repositories

debug:fastapi next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
debug:fastapiSnakeO/claude-debug-and-refactor-skills-pluginSkill99mo agononeA74Claude Code
api-integration-architectsickn33/agentic-awesome-skillsSkill49kyesterdayMITA33Claude Code
printing-press-amendmvanhorn/cli-printing-pressSkill4.9kyesterdayMITA222Claude Code
convex-performance-auditopenclaw/clawhubSkill9.5kyesterdayMITA38Codex
convex-insightsopenclaw/clawhubSkill9.5kyesterdayMITA45Claude Code, Codex
axiom-networkingCharlesWiltgen/AxiomSkill1.3kyesterdayMITA37Claude Code
platform-apex-anonymous-runforcedotcom/sf-skillsSkill1.1k2d agoApache-2.0A119Claude Code