Create a repository

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

Goes well beyond the annotations: discloses the write-mode requirement, the private-by-default behavior, that the repo starts with no commit or branch, and the concrete failure mode (fails on duplicate name). The non-idempotency is also restated in operational terms rather than just as a hint flag.

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?

Front-loaded with the primary action and its scope constraint, and every clause carries real information. It is a single dense sentence chain with semicolons, which costs a little readability but wastes no words.

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?

With no output schema, the description supplies the return shape (get_repo's shape) and the post-creation state (empty repo, no branch). Combined with prerequisites and failure behavior, an agent has everything needed to call it correctly and handle the result.

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 coverage is 100%, and the schema already documents name, private (with default), and description. The description only echoes the private-by-default semantics, so it adds little beyond the structured fields — baseline 3.

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?

States a specific verb+resource (create a repository) plus the key scope constraint: under your own account, not an organization. It separates itself from create_or_update_file, migrate_repo and edit_repo by name, so an agent can route correctly without opening a schema.

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?

Gives explicit when-to-use (push a first commit or add a first file), when-not-to-use (organizations; copying an existing repo with issues/PRs -> migrate_repo; changing settings later -> edit_repo), and the write-mode prerequisite. Nothing is left to inference.

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