codebase-analysis

codebase-analysis is a skill for Claude Code from sequenzia/agent-alchemy. It costs 93 tokens per session (3,228 once invoked), scanned A, original, MIT.

A structured workflow for examining a software project and producing a codebase analysis report. The report covers the project’s architecture, important files, recurring patterns, and recommended actions.

In plain words
What is it for?
It is for mapping a project, explaining what it does, identifying critical files, and recording findings for later use.
Why use it?
It gives developers a repeatable way to understand an unfamiliar codebase instead of relying on scattered file inspection. It also requires the analysis to be saved or otherwise handled after reporting.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: mentions CLAUDE.md; names the AskUserQuestion tool; mentions AGENTS.md.

Runs only inside its plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else. Install the plugin, not this.

Part of the agent-alchemy-core-tools plugin — 6 skills, 4 agents, 1 hook shipped together

Good fit It is for mapping a project, explaining what it does, identifying critical files, and recording findings for later use.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code
/plugin marketplace add sequenzia/agent-alchemy
Claude Code
/plugin install agent-alchemy-core-tools

Made for: Claude Code.

Or install agent-alchemy-core-tools, the plugin that ships this one along with the rest of its 6 skills, 4 agents, 1 hook.

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 codebase-analysis

README.md
[![agentmods](https://agentmods.dev/badge/skills/sequenzia/agent-alchemy/codebase-analysis/github.svg)](https://agentmods.dev/skills/sequenzia/agent-alchemy/codebase-analysis)
Your own site
<a href="https://agentmods.dev/skills/sequenzia/agent-alchemy/codebase-analysis"><img src="https://agentmods.dev/badge/skills/sequenzia/agent-alchemy/codebase-analysis/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 codebase-analysis

Your own site · 80×15
<a href="https://agentmods.dev/skills/sequenzia/agent-alchemy/codebase-analysis"><img src="https://agentmods.dev/badge/skills/sequenzia/agent-alchemy/codebase-analysis.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 93 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,228 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00093 $0.03228
Opus 5.5 $0.00037 $0.01291
Sonnet 5.5 $0.00019 $0.00646
Haiku 4.5 $0.00009 $0.00323

Measured 1mo ago against content hash 193dfe501a3a, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

codebase-analysis 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.

claude/core-tools/skills/codebase-analysis/SKILL.md · 277 lines

How it starts

The opening of the file, as written. The whole thing — 277 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Codebase Analysis Workflow

Execute a structured 3-phase codebase analysis workflow to gather insights.

CRITICAL: Complete ALL 3 phases. The workflow is not complete until Phase 3: Post-Analysis Actions is finished. After completing each phase, immediately proceed to the next phase without waiting for user prompts.

Phase Overview

  1. Deep Analysis — Explore and synthesize codebase findings via deep-analysis skill
  2. Reporting — Present structured analysis to the user
  3. Post-Analysis Actions — Save, document, or retain analysis insights

Phase 1: Deep Analysis

Goal: Explore the codebase and synthesize findings.

  1. Determine analysis context:

    • If $ARGUMENTS is provided, use it as the analysis context
    • If no arguments, set context to "general codebase understanding"
  2. Check for cached results:

    • Check if .claude/sessions/exploration-cache/manifest.md exists
    • If found, read the manifest and verify: codebase_path matches the current working directory, and timestamp is within the configured cache TTL (default 24 hours)
    • If cache is valid, use AskUserQuestion:
      • Use cached results (show the formatted cache date) — Read cached synthesis from .claude/sessions/exploration-cache/synthesis.md and recon from recon_summary.md. Set CACHE_HIT = true and CACHE_TIMESTAMP to the cache's timestamp. Skip step 3 and proceed directly to step 4.
      • Run fresh analysis — Remove the cache manifest file, set CACHE_HIT = false, and proceed to step 3
    • If no valid cache: set CACHE_HIT = false and proceed to step 3
  3. Run deep-analysis workflow:

    • Read ${CLAUDE_PLUGIN_ROOT}/skills/deep-analysis/SKILL.md and follow its workflow
    • Pass the analysis context from step 1
    • This handles reconnaissance, team planning, approval (auto-approved when skill-invoked), team creation, parallel exploration (code-explorer agents), and synthesis (code-synthesizer agent)
    • After completion, set CACHE_TIMESTAMP = null (fresh results, no prior cache)

Read the full file on GitHub · 277 lines

Files

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.

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. 1mo ago First seen · 277 lines · 93 tokens per session scan A 193dfe501a3a

Subscribe to this mod's changes

codebase-analysis is a skill published in the GitHub repository sequenzia/agent-alchemy (45 stars, last pushed 4mo ago), licensed MIT. It adds 93 tokens to every session and 3,228 once invoked, about $0.0004 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 2026-08-30.

Related

Other skills, from other repositories

debugger

Systematic debugging method: 5-step root-cause analysis (capture, isolate, hypothesize, investigate, fix & verify) plus common bug-pattern reference. Use when errors, exceptions, test failures, or unexpected behavior appear. Loaded automatically by the debugger agent.

claude-world/director-mode-lite · 56 tokens

mcp-check

Validate MCP configuration and suggest improvements. Use when MCP servers fail to load, after editing .mcp.json, or when the user runs /mcp-check.

claude-world/director-mode-lite · 36 tokens

project-health-check

Audit project health across 7 dimensions (documentation, test coverage, security, code quality, dependencies, database, build/deploy) producing a scored report with prioritized fixes. Use for periodic checkups, before releases, or when the user runs /project-health-check.

claude-world/director-mode-lite · 57 tokens

debug

Systematic bug investigation with a five-phase framework: reproduce, narrow, diagnose, fix, verify. Supports automated regression bisect via --regression flag. Produces a structured debug report with root cause analysis, regression test, and CQ/Q self-evaluations.

greglas75/zuvo · 55 tokens

ccc-systematic-debugging

Root-cause debugging under one law: no fix without a confirmed root cause. Reproduce, compare, hypothesize, then fix once with a failing test first. Use when investigating a bug, a failing or flaky test, or an error of unknown cause.

KevinZai/commander · 58 tokens

dekko-verify

Sanity-check a suspiciously low or zero call-graph result from dekko (getcallers, getcallees, findusages, impactedtests, unused) before concluding "no callers" or "dead code," or a heritage/throws-provenance result (query supertypes, query subtypes, query throws) that labels something (external) when you expect it to…

aahlijia/dekko · 151 tokens