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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the safety profile is covered. The description adds meaningful behavior beyond that: the stricter title matching and the miss-with-most-recent-episode behavior. It does not cover potential errors (e.g., show not found) but that is minor given the annotations and the tool's read-only nature.

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 two sentences, front-loads the core purpose, and includes only essential details. No fluff or redundancy—every sentence 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 lookup tool with an output schema and annotations covering safety and idempotency, the description covers the key aspects: what it returns, how to specify the show (id or title), timezone conversion, and the miss behavior. It doesn't mention error cases, but that is not critical given the output schema exists and the tool is read-only. The description is adequate for an agent to invoke it correctly.

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 the baseline is 3. The description adds extra value by clarifying that title resolution uses a stricter single-match search than tvmaze_search_shows, which is not fully captured in the schema. It also ties the timezone parameter to the viewer timezone conversion. This goes beyond schema details, hence a 4.

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 opens with a clear verb-resource pair ('Report when a show's next episode airs') and explicitly notes it accepts either an id or title, distinguishing it from siblings like tvmaze_get_episodes (which lists episodes) and tvmaze_search_shows (which is a broader search). The purpose is unambiguous and differentiates itself.

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 gives clear context: it mentions the stricter single-match search relative to tvmaze_search_shows, implying when to use this tool for title resolution, and explains the miss behavior for off-season shows. However, it does not explicitly state 'use this when you need the next air date' or contrast with all alternative tools, leaving some inference to the agent.

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