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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false), so the description is not carrying the safety burden. It does add one genuinely useful behavioral fact beyond the annotations: the update is partial/PATCH-style ('Only the fields you pass are changed'). It omits any auth/permission or approval requirements, and says nothing about the approval_id flow.

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?

Very short, but the first sentence is a grammatical fragment ('When a saved place's details changed') rather than a complete clause, and it does not front-load a clear action statement. It is compact but the structure undermines readability.

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 safety, the description is not required to explain returns. It covers the core partial-update semantics, but for a 9-parameter mutation it says nothing about prerequisites (e.g., the approval_id requirement) or how missing/unset fields are treated, leaving it minimally adequate.

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% (all 9 params documented inline), so the baseline is 3. The description adds only the general partial-update rule that applies across all optional fields; it gives no per-parameter meaning beyond the schema.

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?

The name/title ('places.update' / 'Update Place') carries the verb+resource, while the description only supplies a triggering condition ('When a saved place's details changed') rather than stating the purpose directly. The phrase 'Only the fields you pass are changed' implies a partial update, but the description neither opens with what the tool does nor distinguishes it from the many other *.update siblings (addresses.update, contacts.update, notes.update).

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 opening clause gives an implied when-to-use trigger ('When a saved place's details changed'), which is more than nothing. However, it offers no alternatives, no when-not condition, and no mention that places.create/delete exist for the other operations.

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