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 non-obvious behavior the agent cannot see structurally: a duplicate call returns the existing board job, and the call silently marks a matching Following item as read. The side effect on Following state is exactly the kind of disclosure that prevents surprise downstream.

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?

Three sentences, the primary action front-loaded, with the ID disambiguation placed immediately after. The final sentence bundles two unrelated exclusions and the mark-as-read side effect, which reads slightly compressed but wastes no words.

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?

An output schema exists, so return values need no prose, and the annotations cover the safety profile. What remains for the description to cover — ID semantics, idempotent duplicate behavior, and the Following side effect — is all present.

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 0% with a single required string, so the description must carry the meaning, and it does: it specifies the value is opening.id rather than the Following row ID. That disambiguation is the only thing an agent could get wrong here, and it is stated explicitly.

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 ('Add an indexed opening to the board') and pins down which identifier is consumed, which an agent cannot infer from the name alone. It doesn't contrast itself with the nearby jobs.add sibling, so the boundary between the two add-paths is left implicit.

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?

'after the user chooses it' hints at the triggering context, and the exclusion ('does not apply to the employer or send email') rules out two misreadings. However, no alternative tool is named, so an agent facing a job/opening add decision gets no explicit routing rule.

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