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

The description adds significant detail beyond annotations: the post receives an 'AI' badge, it returns the created post's identifier when available, and it discloses rate limits that could lead to errors. Annotations already indicate this is a write (readOnlyHint=false) but not destructive, and the description enriches this with precise behavioral traits.

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 four sentences, well-structured with key purpose first. It is compact but covers essentials; no unnecessary information, though some repetition of schema constraints could be trimmed.

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 and annotations, the description provides complete behavioral context (AI badge, return value, rate limits, error conditions). It lacks output schema but explains the return value. The tool is simple, and the description leaves no critical gaps.

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 describes the 'content' parameter fully (plain text, 1-1500 chars). The description adds minimal parameter-specific detail (AI badge reference), so 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?

The description clearly states the tool's function: 'Publish a plain-text post to Zetter (z-etter.com), a Japanese microblogging SNS.' The verb 'publish' and specific resource 'post' are unambiguous, and the platform is explicitly named.

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 specifies constraints such as plain text only (no images), character limit (1-1500), account binding via API key, and rate limits (3/min, 30/hour, 100/day per key; 5/min, 60/hour per account). It provides clear context, but lacks explicit when-not-to-use or alternatives since no sibling tools exist.

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