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

Annotations already declare readOnlyHint, idempotentHint and a closed-world non-destructive read, so the safety profile is covered. The description adds genuine behavioral context beyond that: the hard 16-segment ceiling, the default 2-before/5-after window, and the fact that each returned segment carries its own citable URL. It does not describe ordering or what happens when the window runs off the end of an episode.

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?

Two tight sentences, front-loaded with the resource and its scope, then the accepted anchor forms and defaults. Every clause carries information — the segment cap, the anchor sources, the defaults, and the citation affordance — with no restatement of the title.

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?

No output schema exists, but with full annotation coverage and 100% schema description coverage the description only needs to sketch the return shape, which it does by noting each segment has its own URL to cite. The main residual gap is failure behavior for an out-of-range timestamp, anchor or segment index, which an agent would want to know before calling.

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 and the schema already documents 'at', 'before', 'after' and 'episode'. The description adds real value the schema does not: the combined clipping rule of 16 segments total (max 5 before + max 10 after + the anchor) and the default window of 2/5, which lets an agent reason about output size without reading both parameter bounds.

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 ('Returns up to 16 consecutive transcript segments from one episode') plus the anchor types accepted, so an agent can tell this is a windowed fetch around a known point rather than a search. It does not explicitly name sibling tools like search_transcripts, so differentiation is inferred from the anchor semantics rather than stated.

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 effectively tells the agent when to use it by naming the inputs it consumes: 'a segment_index from search results, or a passage url or its #t- anchor' — establishing a clear search-then-excerpt workflow and distinguishing it from search tooling. It stops short of stating explicit exclusions or naming the alternative tool for other cases.

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