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

readOnlyHint=true already establishes the safe-read profile, so the description is free to add the non-obvious traits: availability events represent can/cannot-work declarations and may include recurring patterns materialized into the window. It doesn't cover pagination or result size limits, but it meaningfully exceeds the annotation baseline.

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 tight sentences, front-loaded with purpose and scope before defaults, plus the underlying endpoint for traceability. No filler or redundancy.

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 read-only, four-optional-parameter list tool with no output schema, the description covers purpose, default scoping, and the recurring-pattern nuance. Return shape and pagination behavior are unspecified, but the annotations and schema carry most of the remaining burden.

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 start/end, user_id and include_all are already documented in detail, including date formats and the manager restriction. The description restates the caller/two-week defaults but adds no format or scoping detail the schema lacks — baseline 3.

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 ('List availability events') and then defines the resource in domain terms — 'when people said they can or cannot work' — which disambiguates it from shift and time-off listing tools. It stops short of naming a sibling explicitly, so an agent must still infer the boundary versus wheniwork_list_time_off_requests.

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 concrete usage context: defaults to the caller and a now-to-two-weeks window, and the include_all parameter is flagged manager-only. There is no explicit when-not guidance or named alternative tool, so it's clear context without exclusions.

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