bdesign_timeline_usage

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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds one genuinely useful behavioral fact — this reads actual Timeline state rather than following a Canvas latest output, and it does not create an index node — but says nothing about return shape, latency, or what 'active takes' and 'source ranges' contain.

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 short sentences, front-loaded with the core purpose and with no filler. The second sentence is dense but earns its place by flagging the Canvas divergence; minor ambiguity in 'index node' costs it a point.

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?

Given only a readOnlyHint annotation and no output schema, the description should convey enough about the result to let an agent decide to call it and interpret the response. It names the data domains (media usage, active takes, source ranges) but not the structure or units, and leaves the sole parameter unexplained.

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?

The single parameter projectId has 0% schema description coverage, and the description never mentions it or explains whether it is required for scoping or what happens if omitted (required count is 0). With low coverage the description is expected to compensate, and it does not.

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 ('Read') and resource ('actual Timeline media usage, active takes and source ranges'), which is concrete enough for an agent to identify the operation. The closing sentence distinguishes it from sibling Canvas tools ('does not follow a Canvas latest output'), though the phrasing is jargon-heavy and the exclusion is framed negatively rather than as a positive scope.

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?

Usage is only implied: read real Timeline usage when you don't want a Canvas-derived latest output. No explicit 'use this when…' condition and no named alternative (e.g., bdesign_canvas_get, bdesign_canvas_view) that the agent should pick instead. The exclusion hints at the boundary but leaves selection to inference.

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