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

readOnlyHint=true already tells the agent this is a safe read. The description adds value beyond that by disclosing the return contents and a real workflow gotcha (empty timeline causes downstream continuity passes to fail), which is genuinely useful behavioral context. It does not cover error behavior for a non-existent seq_id.

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 sentences, both earning their place: the first defines the payload, the second front-loads the actionable check. No filler or 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?

With no output schema, the description correctly enumerates the returned fields and ties the tool into the continuity workflow, which is sufficient for a 1-parameter read tool. Minor gap: it does not say what happens when the seq_id is unknown or how a missing/empty timeline is represented.

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% and there is a single parameter, so the schema already documents seq_id including its provenance (lab_create_sequence/lab_list_sequences). The description adds nothing further about the parameter, so the baseline 3 applies.

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 (get) and resource (sequence) with explicit scope ('ONE sequence in full') and enumerates the returned payload: timeline, audio_tracks, transitions, duration_seconds, render status. The 'ONE' framing distinguishes it from the sibling lab_list_sequences, which returns many.

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 pre-flight condition: check `timeline` here before starting a continuity pass, and explains why (an empty timeline is the most common cause of the pass refusing). It does not explicitly name sibling alternatives such as lab_list_sequences, so it stops short of full when/when-not routing.

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