list_repos

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

Annotations already provide readOnlyHint=true, so the read-only nature is captured. The description adds useful behavioral context by specifying that it only lists repositories indexed via index_repo and by declaring the exact return contents, which goes beyond the annotation and helps set expectations.

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?

The description is three sentences, front-loading the primary action first, then the returned fields, then the scope limitation. Every sentence contributes essential information without redundancy or filler.

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 zero-parameter, read-only list operation with no output schema, the description covers all necessary context: what is listed, which fields appear, and which repositories are excluded. Nothing appears missing for an agent to call the tool confidently.

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 tool has zero parameters, so the baseline is 4. The description adds no parameter-specific details, but none are needed because there is nothing for the caller to configure; the framing of the return contents makes the no-input action clear.

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 opens with a specific verb, 'List', and the resource 'GitHub repositories indexed via index_repo,' immediately clarifying the tool's function. It further distinguishes the tool from siblings like list_datasets by enumerating exactly what is shown: repo name, HEAD SHA, dataset count, total rows, and dataset names.

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?

The description explicitly defines the scope: 'Covers repos indexed with index_repo only; a dataset added by index_local is not listed here.' This gives clear guidance on when to use the tool, though it stops short of naming an alternative tool explicitly, leaving the agent to infer index_local as the alternative for local datasets.

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