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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds only a light content summary (eligibility, deadline, funder link), which largely duplicates the output schema rather than adding traits like missing-record behavior or whether the link is external.

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?

A single sentence with no filler, front-loaded with the verb and resource and finishing with the returned fields. 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 simple single-parameter read tool with full annotations and an output schema, this is close to sufficient — the agent knows it reads one record safely. The missing piece is an explicit pointer that the slug must come from a prior search call, though the schema covers it.

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% and the schema already explains the slug format, provenance, and that it is not an internal identifier. The description contributes nothing about the parameter, so the baseline of 3 applies.

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 ('Return one opportunity') and enumerates what comes back: eligibility, deadline, funder link. It implies single-record lookup versus the list-oriented opportunity_search sibling, but never names that sibling to make the distinction explicit.

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?

Usage is only weakly implied — 'one opportunity' signals lookup rather than search, but there is no statement of when to prefer it over opportunity_search or funder_profile. The key prerequisite (obtain the slug from a prior opportunity_search result) appears only in the schema's parameter description, not in the tool description.

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