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

Annotations cover the safety profile (not read-only, not idempotent, not destructive). The description adds the crucial behavioral fact that the raw key is returned only once, which is not derivable from annotations and directly affects how the agent must handle the result. It does not mention auth requirements or rate limits.

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 zero filler; the core action and the one-time-return caveat are both front-loaded. 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?

For a one-parameter creation tool with no output schema, the description covers the essential return behavior (raw key shown once). It is slightly thin on the fact that the key can later be identified via list_mcp_keys, but nothing needed to invoke 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% and the single name parameter is fully documented in the schema, so baseline 3 applies. The description adds only a faint hint (naming for a second client) and no format or constraint details 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?

States a specific verb and resource ("Create another MCP key") and even gives the identifier prefix mcpk_, which distinguishes it from the sibling create_api_key. It is clear and concrete, though it never explicitly names the API-key sibling it could be confused 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?

"e.g. for a second client" implies a use case (multiple clients/keys), which is weak but real guidance. There is no explicit when-not condition, no prerequisites, and no pointer to list_mcp_keys or delete_mcp_key as alternatives.

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