check_credentials

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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds genuinely useful context beyond that: the check is performed by making a live API request for one program, so the agent understands it consumes a network call and depends on external state rather than inspecting a local file.

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?

One front-loaded sentence, no filler, and the mechanism follows the purpose immediately. Every clause earns its place.

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 an output schema present, return-value details (e.g. what a failed check looks like) need not be restated, and with zero parameters there is no input to document. The only remaining gap is any credential/permission prerequisite or rate-limit note, which is minor for a read-only diagnostic.

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 takes zero parameters, so there is nothing for the description to disambiguate; baseline is 4. Nothing in the description contradicts the empty schema.

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 and resource (check the stored HackerOne API token) and even the mechanism (by requesting one program), which no sibling tool does — siblings are all list/get data-retrieval tools. It's clear what the tool accomplishes without needing the schema, though it doesn't explicitly name a sibling it contrasts with.

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?

Usage is implied — you call this to validate that stored credentials still work — but there is no explicit statement of when to use it, when not to, or what to do instead if the check fails. Adequate but leaves the trigger condition to inference.

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