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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety and live-data behavior are covered. The description adds the useful constraint that the section must be a valid value sourced from mirror_sections and that only public sections are covered, but says nothing about freshness, pagination, or result volume.

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?

One front-loaded sentence with no filler: purpose first, then the input constraint. 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 single-parameter read tool with an output schema and safety annotations, the description covers purpose, scope, and input sourcing adequately. Missing only minor details such as whether results are limited or paginated, which the output schema may partly cover.

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 0% and the single 'section' property is a bare string with no enum, so the schema gives the agent nothing. The description compensates by telling the agent where valid values come from (mirror_sections) and that only public sections qualify, though it never shows the expected string format.

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+resource+scope: current headlines for one public section of Mirror. It also names the sibling it depends on (mirror_sections) for valid section values, which helps separate it from that sibling. It does not, however, distinguish itself from the nearby mirror_news or mirror_article tools.

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?

Gives a concrete prerequisite that shapes the call sequence: the section value must come from mirror_sections, implying the agent should call that tool first. There is no explicit statement of when to prefer this over mirror_news or mirror_article, so it falls short of the top band.

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