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

Annotations already declare readOnlyHint=false, destructiveHint=true and idempotentHint=true; the description goes beyond them by disclosing the merge semantics ('merged by key; keys sent replace their current values'), which explains exactly which state is overwritten and why repeated calls are safe. It does not confirm or deny the destructive hit on keys omitted from the call, but the core mutation behavior is covered.

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 with no waste, and the core behavior plus merge semantics are front-loaded. Every clause earns its place.

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 destructive nested-object mutation with no output schema, the definition covers the write semantics but leaves out two things an agent needs: how to discover valid prop keys (e.g., via inspect_composition) and how it differs from update_composition. Adequate but with a real gap.

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 only 33% — only 'token' is documented. The 'props' object is an untyped nested object with no key list or value format, and the description only says values are merged by key; it never says what prop keys exist or what the 'id' parameter identifies. The merge rule is helpful but does not compensate for the untyped props payload.

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 ('Sets prop values on a composition') and adds a useful conceptual anchor: these are the same values the user's controls change. It does not, however, distinguish itself from the sibling 'update_composition', so an agent must still guess which mutation to use.

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 by 'the same values the user's controls change', which hints at the intent but gives no explicit when-to-use rule, no prerequisites, and no comparison against update_composition or inspect_composition. The agent is left to infer.

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