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

Annotations already declare readOnlyHint=false, destructiveHint=true, openWorldHint=false. The description adds the partial-update rule ('Only the fields you pass are changed'), which is useful but largely inferable from the schema marking only the two ids as required. It never explains what the destructiveHint actually implies (overwritten values, irreversibility), so behavioral coverage remains thin despite the annotation relief.

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 short sentences, each carrying a distinct fact (purpose, update semantics, id source), with the core action front-loaded. Nothing is padded or redundant.

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 definition still covers purpose, mutation semantics, and id acquisition, and annotations cover the safety profile. It is slightly short on what a successful update returns or what happens with an unknown id, but nothing essential for invoking the tool 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%, so every parameter (name, type, action, prompt, ids) is already documented with constraints like max length and the type enumeration. The description adds only the id-provenance hint, which the schema also states, so it does not exceed the baseline.

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 ('Update') and resource ('an existing suggested message'), which clearly separates it from add_suggested_message and remove_suggested_message in the sibling list. It does not explicitly name those siblings, but the resource anchoring makes disambiguation easy.

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 prerequisite workflow: 'Get the id from list_suggested_messages,' naming the sibling that supplies the required suggested_message_id. There are no when-not-to-use conditions, so it stops short of the top tier.

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