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

With no annotations provided, the description carries full behavioral disclosure. It reveals pricing implications ('Paid model call'), rate limits and refusal status (401), output length cap (~400 tokens), caching behavior, and the important side-effect guarantee that nothing is sent. This is unusually transparent.

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?

Every sentence adds value: purpose, output shape, side-effect guarantee, sibling routing, rate limits, token cap, and caching. Information is front-loaded and the description stays compact despite covering many operational details.

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?

Despite having no annotations and no output schema, the description covers the return format, behavioral constraints, rate limits, caching, and usage boundaries. An agent has enough information to decide whether to call this tool and to interpret the response.

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%, so the schema already documents both parameters. The description adds context about the brief ('A sentence or two is enough') but does not materially expand parameter semantics beyond the schema. Baseline 3 is 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?

States a specific verb and resource: 'Write a business email body from a short brief.' It immediately clarifies scope by saying the result is the body only, no subject line, no recipient, and nothing is sent. This clearly differentiates it from generate_text and humanize_text.

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?

Provides explicit selection guidance: 'Choose this over generate_text when the output should be a whole email; use humanize_text to rewrite an email you already drafted.' This tells the agent exactly when to pick this tool and when to pick an alternative.

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