Start a browser login

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

Annotations only cover openWorldHint and destructiveHint=false; the description carries the real behavioral load by disclosing that the call is asynchronous and returns immediately with a job id, one-time code and URL, that a human must complete sign-in/2FA/Authorize, and the polling cadence for completion. This is exactly the non-obvious behavior an agent needs.

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?

Three dense sentences: purpose first, then the async return contract, then the follow-up polling action. Every clause carries actionable information with no 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?

There is no output schema, and the description compensates by naming the returned artifacts (job id, one-time code, URL) and the terminal condition for polling (running is false). For a two-parameter async login tool, nothing needed to invoke and follow through correctly is missing.

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%, so the baseline is 3, but the description adds meaning beyond the enum by mapping each service to its concrete login mechanism (gh auth login --web, npm login --auth-type=web), implying each service behaves differently. No detail is added for openBrowser, keeping it at 4.

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?

Specific verb ('Start the browser-based login') plus the exact resource, with the supported services enumerated (github, npm, pypi, crates). An agent can distinguish this from job_status, preflight, or setup_trusted_publishing without reading the 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 the operative workflow: call it, hand the code/URL to the user, then 'Poll job_status every 1–2 minutes until running is false,' naming the sibling to use next. It does not state when-not to use it (e.g. if credentials already exist), so it stops 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.