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

Beyond the readOnlyHint/openWorldHint annotations, it discloses upstream error behavior (id-only or wrong slug is a 404) and an important omission rationale: episode cover images are signed and expiring so they are deliberately excluded, with only catalog metadata exposed. That is genuine behavioral context an agent could not derive from the annotations, though it says nothing about response size or pagination for long episode lists.

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?

Front-loads the identity and payload, then the calling constraint, then the omission caveat — a sensible order with no filler sentences. The long enumeration of return fields is somewhat redundant given an output schema exists, but it is packed into one clause rather than sprawling.

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, three-parameter detail tool with a full output schema and explicit safety annotations, the description covers everything an agent needs: what comes back, how to key the request, what fails, and what is intentionally absent. No meaningful gap remains.

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 100%, so the baseline is 3; the description largely restates the schema's pairing constraint ('both title_id and slug from the same card', 404 on mismatch) rather than adding new meaning. It adds no extra detail on the optional language parameter or how locale interacts with localised slugs beyond what the schema already documents.

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?

Names a specific verb and resource ('Get one FlickReels title') and enumerates the payload: title, cover, synopsis, episode count, release date, tags, full episode list with per-episode fields, and a related shelf. The 'FlickReels' scoping plus 'slug+id keyed' detail-fetch framing separates it cleanly from browsing siblings like flickreels_home or flickreels_shelf and from other catalog providers (reelshort_movie, tmdb_movie).

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 invocation rule — 'Pass both title_id and slug from the same card' — and warns that an id-only request or wrong slug yields a 404, which tells the agent when the call will fail and how to avoid it. It does not explicitly say when to prefer this over a sibling (e.g., after flickreels_classify resolves a card), so it falls short of full when/when-not guidance.

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