ms_check_auth

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

The description adds meaningful behavioral context beyond the readOnlyHint annotation: it states the tool never reveals secret values and only reports which variables are set. It also specifies the exact JSON return shape (ready, missing, required), making the tool's behavior predictable and safe.

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 short sentences each carry distinct value: the tool's purpose, a critical security guarantee, and the return format. The text is front-loaded with the main action and contains no filler or redundancy.

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-argument, read-only check with an output schema, the description fully equips an agent to select and invoke the tool correctly. It covers what the tool does, what it does not do, and what the response looks like.

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 accepts zero parameters, so the input schema fully defines the call surface; the rubric baseline for zero-parameter tools is 4. The description adds no parameter-level details because none are needed.

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 uses a specific verb ('check') and a clear resource ('credentials present in the environment'), and it clarifies that the tool only reports presence, not secret values. It stands apart from siblings like ms_set_key by emphasizing it does not reveal secrets, though it does not explicitly name alternatives.

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 intended use as a credential preflight check is implied by the description, and the explicit statement that it does not reveal secrets helps rule out using it as a credential fetcher. However, there is no explicit guidance about when to run it before other tools or when to prefer an alternative.

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