SetHighlightNote

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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=false, so safety is largely covered. The description still adds value by explicitly saying the operation can replace or remove an existing note (a mutation of prior state) and by clarifying that highlights themselves cannot be created via this API.

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 operation set, with zero filler. Every clause carries information an agent needs.

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 an output schema present and annotations covering the safety profile, the description only needs to convey purpose, mutation semantics, and scope limits — all of which it does. It could go further by naming the sibling used for the alternative operation, but nothing essential 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?

Schema description coverage is 100%, and the schema already documents both parameters, including the empty-string-to-remove convention. The description adds no syntax or format detail beyond what the schema provides, so the baseline of 3 is appropriate.

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?

Names a specific resource (the note on a highlight) and all three operations (add, replace, remove) in a single clear sentence. It also states a scope boundary ('Matter's API can't create highlights'), which distinguishes it from any highlight-creation intent, though it never names a sibling tool as an alternative.

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?

Provides implied usage context by pointing to ListHighlights for obtaining the highlight_id, and the note parameter implicitly defines the remove case. There is no explicit when-to-use/when-not guidance versus siblings like Matter_DeleteHighlight or the tag tools.

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