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

Annotations already mark this as a non-read-only, non-idempotent, non-destructive creation. The description adds genuinely useful behavior beyond that: the raw key is returned exactly once and cannot be retrieved later, which tells the agent to surface/store the value immediately. It stops short of stating auth requirements or key 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 sentences, zero filler, and the most actionable fact (one-time retrieval) is front-loaded right after the purpose. Nothing to trim.

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 full schema coverage and no output schema, the description covers the essential lifecycle detail (one-time reveal). It could mention whether the key is scoped/permission-bound or requires a particular plan, but nothing critical for a correct invocation 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 (max 100 chars), so the baseline of 3 applies. The description adds the key-format prefix, but no naming conventions or constraints beyond what the schema already carries.

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 a new MCP key') and even names the returned key format prefix (mcpk_…). It is clearly differentiated from generic key creation only implicitly, however — the sibling create_api_key is not contrasted, so the agent must infer the distinction from the name alone.

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 description gives no guidance on when to create an MCP key versus create_api_key, nor any prerequisites such as plan limits or existing key count. With several key-management siblings (create_api_key, list_mcp_keys, delete_mcp_key), the absence of selection guidance is a real gap.

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