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

Annotations already cover safety (readOnly, idempotent, non-destructive), and the description adds genuinely new behavioral facts: the call is free and it is gated on readiness states (ready video / completed job / combinedReady). It does not disclose response shape, size limits, or behavior when the video is not yet ready.

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 short sentences, no filler, with the core action front-loaded and the readiness gate placed after it. 'Free' earns its place as a decision-relevant fact.

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?

With 4 parameters, 25% schema coverage, and no output schema, the description leaves real gaps: the meaning of the format enum and the effect of timestamps are unexplained, and the return value (the entire point of a transcript fetch) is never characterized. The readiness gating is the strongest part; the output-side semantics are missing.

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 25%, so the description must compensate, and it only partly does: it explains videoId ('a video id returned by get_transcription, or all'). Nothing is said about 'format' (what 'ai-ready' or 'vtt' actually produce) or 'timestamps', both of which are undocumented in the schema as well.

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?

Specific verb+resource ('Fetch transcript content') with explicit scope: one ready video or all ready results in a completed job. It hints at the pipeline relationship to get_transcription, but never states how this differs in output from that sibling, so an agent must infer the boundary.

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?

Provides concrete preconditions for use: video must be ready, job must be completed, and 'all' requires combinedReady to be true. It also points at get_transcription as the source of the video id. It stops short of naming alternatives or when-not-to-use cases, so it is clear context rather than full routing guidance.

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