repo_brief

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the behavioral burden, and it does so reasonably well: it says the tool ranks files, supports four modes, reports several signals, and suggests next steps. It does not explicitly state that it is read-only or discuss stale-index/performance caveats, but the orientation framing makes the non-mutating nature clear.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two compact, front-loaded sentences say what the tool does, how it ranks files, what signals are included, and when to invoke it. Every clause carries useful information; there is no fluff.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given that the output schema is absent and there are no annotations, the description is fairly complete: it communicates the purpose, modes, result ingredients, and suggested next tools. It could be slightly more specific about how the limit, include flags, and worktree interact with the summary, but the schema already documents those.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The description adds useful meaning to the main 'mode' parameter by explaining that 'spine' means central coupling and that the other modes are churn, god_modules, and refactor_candidates. The include and worktree parameters are already well described in the schema, so the description's additional mode semantics meaningfully improve parameter understanding.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly says this is an orientation tool for an unfamiliar repo, what it does (returns ranked files by mode), and what the output contains (size/coupling/churn/memory signals and suggested next tools). 'Start here when you don't know the codebase' helps separate this from more targeted sibling tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It explicitly tells the agent when to use it: 'Start here when you don't know the codebase.' It doesn't name specific alternative tools and say when not to use it, but the starting-point framing provides enough context for this orientation tool.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.