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

Annotations already declare idempotentHint=true and destructiveHint=false, but the description adds critical details beyond those: exact file path, chmod 600, persistence across restarts, hosted response 'persisted: false', and the requirement to send an Authorization: Bearer header. This is rich operational context the annotations do not convey.

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 with the core purpose and uses clear paragraphs for environment-specific behavior. It is somewhat long, but every sentence provides operational necessity—no filler. Slight verbosity around the hosted section keeps it from a 5.

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 single-parameter tool with full schema coverage, annotations, and an output schema, this description is complete. It covers the exact trigger (after create), environment differences, persistence behavior, and how to handle the non-persistent case, leaving no gaps for correct invocation.

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 schema already documents api_key as 'Full API key string from manage_api_key.' The description repeats that nearly verbatim, adding no new meaning. Baseline 3 is appropriate because the schema carries the parameter semantics.

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 ('Activate an API key') and clearly distinguishes from its sibling manage_api_key by positioning this as the step after creation. An agent can immediately tell this tool is for enabling/persisting a key, not for creating or managing it.

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?

Explicitly instructs to call this after manage_api_key(action='create') returns a raw_key, and provides environment-specific guidance: local persistence vs. hosted per-request authentication. This leaves no ambiguity about when to use the tool and what to do with the result.

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