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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds genuinely useful non-obvious behavior: word start/end values are seconds from source media start, default limit is 20, and the formatter omits the unbounded fullText duplicate. That last detail is exactly the kind of hidden behavior an agent cannot infer from structured fields.

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, zero filler, front-loaded with the core action before pagination mechanics and the formatting note. Every sentence carries distinct information.

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 an output schema present, return values need not be explained, and the description covers pagination, units, and formatting caveats adequately for a 4-parameter read tool. The only remaining gap is the absence of routing guidance relative to editorial_inspect_transcript, which mildly weakens completeness.

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, but the description adds meaning beyond the schema: it explains that after accepts pagination.nextCursor from a previous response (linking parameters across calls) and clarifies the time unit of the word timing values. It does not restate limit/before semantics, which the schema already handles.

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 ('Read exact source-time transcript words') with a scoping qualifier ('in bounded utterance pages'), which is far more informative than the title. It does not distinguish itself from the similarly named sibling editorial_inspect_transcript, so it stops short of a 5.

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 operational usage for pagination ('pass pagination.nextCursor as after for later pages') and the default page size, which tells the agent how to iterate. However it gives no when-to-use versus alternatives guidance and never mentions editorial_inspect_transcript or any sibling, so usage is only implied.

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