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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds one genuinely useful disclosure beyond them — 'Headers are never returned' — implying no auth secrets leak in the response. It says nothing about ordering, pagination, or how many endpoints come back, so the behavioral picture remains partial.

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?

Two short sentences with no filler, and the resource definition leads. The first sentence is grammatically awkward ('Calls into your own systems the tester may make'), which slightly slows parsing but costs no real space.

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 simple one-parameter read tool with no output schema, the definition covers the domain and the notable header omission. It is still incomplete on the basics: it never states that endpoints are returned for the given project, nor what identifying fields each record carries.

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 description coverage is 100% for the single projectId parameter, so the schema carries parameter meaning on its own. The description adds no scoping or format detail beyond what is already structured, making the baseline 3 appropriate.

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 defines the resource ('calls into your own systems the tester may make during a run') rather than the operation; it never says the tool returns a list, leaving the verb to be inferred from the name and title. The domain definition does help distinguish it from siblings like list_tests or list_credentials, but the action itself is only implied.

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?

There is no when-to-use guidance and no mention of related siblings such as add_endpoint or delete_endpoint, which an agent would plausibly confuse with this tool. The example ('create a voucher') clarifies what an endpoint is, not when to call this tool.

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