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

Beyond the annotations (readOnlyHint=false, destructiveHint=false, idempotentHint=false), the description discloses that the API key is shown once, that a claim link is returned, that daily limits are provided, and how credential propagation differs on hosted vs external MCP. These are important behavioral details for a setup/authentication tool.

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?

The description is front-loaded and dense, covering creation, output, credential behavior, and parameters in a few sentences. It has some redundancy, e.g. 'no key and no human' is repeated at the end as 'needs no credential', and the name constraints duplicate the schema.

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 registration tool with no output schema, the description is complete: it explains what is created, what values are returned, how the credential is used afterward, and the parameter expectations. Nothing essential for invoking it 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 all three parameters are already documented in the input schema. The description repeats the name length/character constraints and notes that contact_email and intended_use are optional, but adds little meaning beyond the 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?

The description states a specific verb and resource: 'creates a sandbox workspace of your own and returns its API key'. It distinguishes this from credential-requiring siblings by saying it needs 'no key and no human', and names the concrete outputs (key, daily limits, claim link).

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?

It explains that the tool is public and needs no credential, and that on the hosted MCP server the session continues using the new key while elsewhere the key must be sent as x-api-key. That is clear context, but it never explicitly says when to prefer this over a credential-bearing flow such as use_api_key.

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