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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the description correctly spends its words elsewhere: it discloses the returned shape and the empty-state behavior ('A thread with no timeline yet returns an empty cuts list'). With no output schema, that empty-state note is genuinely useful and prevents an agent from misreading an empty result as an error.

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 tight sentences: return shape first, then usage routing, then edge case. No filler and 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?

For a single-parameter read tool with no output schema, the description supplies the entire return model (cuts, active cut, clip field list) plus the empty case. Nothing needed to call or interpret the result is 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?

Only one parameter, and the schema fully documents it ('Thread id, from list_threads') at 100% coverage. The description adds nothing about threadId beyond the schema, so the baseline of 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 (Show) and resource (a thread's timeline) and enumerates exactly what is returned: cuts, the active cut, and the per-clip fields. This clearly separates it from siblings like get_thread or render_timeline, which are about different resources or actions.

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 sentence 'Use clip ids with reorder_clips and remove_clips' tells the agent the downstream purpose of this call. There is no explicit when-not or comparison against get_thread, but the usage context is clear and actionable.

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