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 agents/denfry/codebase-index/codebase-indexgit clone --depth 1 https://github.com/denfry/codebase-indexWhat 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 | $0.00063 | $0.01711 |
| Opus 5 | $0.00032 | $0.00856 |
| Sonnet 5 | $0.00013 | $0.00342 |
| Haiku 4.5 | $0.00006 | $0.00171 |
Grade A, and why
codebase-index scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 149 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Codebase Index
Use this skill first for codebase questions.
Never scan the entire repository before searching the index.
When to use
Invoke this skill before reading any files when the user asks about this project's code:
- "where is X implemented" / "find X" / "locate the X function"
- "how does X work" / "explain the X flow"
- "what breaks if I change X" / "what depends on X" (impact analysis)
- "who calls X" / "references to X"
- "trace the data flow of X"
- "why is this error happening" (error/stack trace)
- "explain the architecture" / "give me an overview"
- Any question about symbols, files, dependencies, or refactoring scope
Do not use it for: editing files, running the application, or non-code questions.
How to call the CLI
Use the codebase-index CLI directly, or the bundled cbx wrapper:
codebase-index search "$QUERY" --json
Pick the subcommand by intent:
| User intent | Command |
|---|---|
| "how does X work" / "explain X" / "walk me through" | codebase-index explain "$QUERY" --json |
| overview / architecture | codebase-index explain "architecture overview" --token-budget 3000 --json |
| general / unsure | codebase-index search "$QUERY" --json |
| keyword / "where is" | codebase-index search "$QUERY" --json |
| a specific symbol name | codebase-index symbol "<name>" --json |
| "who calls / references" | codebase-index refs "<name>" --json |
| "what breaks if I change" | codebase-index impact "<file-or-symbol>" --json |
| visual graph / "open graph" | codebase-index graph "<file-or-symbol>" --open |
explain has a higher default token budget (2200) and HOW_IT_WORKS intent weights — use it whenever the question is about understanding behavior or flow.
For search, pick a --mode when the intent is clear:
--mode symbol— pure symbol lookups (faster, no FTS noise)--mode fts— text/keyword queries where symbol names don't matter--mode hybrid— default; best for mixed queries
Natural-language kind words such as method, function, class, interface,
enum, and type constrain the symbol retriever inside search.
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 First seen · 149 lines · 63 tokens per session scan A c6969c90bc48
codebase-index is an agent published in the GitHub repository denfry/codebase-index (7 stars, last pushed 1mo ago), licensed MIT. It adds 63 tokens to every session and 1,711 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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