repo_overview

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds useful behavioral context: it performs a filesystem scan, requires no index, and should only be called once per session. This goes beyond the structured annotations without contradicting them.

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 dense, front-loaded sentences cover purpose, scope, outputs, mode of operation, and usage frequency. Every clause adds value, and there is no filler or repetition of schema details.

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?

For a tool with a single optional parameter, no output schema, and safety annotations already present, the description is complete. It tells the agent what results to expect, how the tool operates, and how often to use it. Nothing critical is missing for correct invocation.

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?

Schema description coverage is 100% and the single optional parameter 'source' is already explained well in the schema, including when to omit it. The description does not add parameter-specific detail, but it does not need to because the schema carries the meaning. Baseline 3 is appropriate.

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 states the tool provides orientation for an unfamiliar codebase and enumerates specific outputs: languages by file count, frameworks, manifests, entry points, and build/test/run commands. This resource and scope are specific enough to distinguish repo_overview from sibling tools like module_summary or list_sources.

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 says 'Call once per session,' which gives clear usage frequency guidance. It also indicates the tool is for unfamiliar codebases and does not need an index, implying it suits initial exploration rather than repeated targeted queries. It does not explicitly name alternatives or exclusion conditions, so it falls short of a 5.

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