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

Annotations already declare the safety profile (readOnly=false, destructive=false, idempotent=false, openWorld=false). The description adds useful PATCH semantics ('Only the fields you pass are changed') that annotations do not convey, but it omits the notable approval workflow implied by the approval_id parameter (human-approved, single-use request), which is a meaningful behavioral trait for a mutation tool.

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 terse sentences with no filler, appropriately sized for the tool. Front-loading is slightly off: the key partial-update fact is in the second sentence while the first states a condition.

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?

An output schema exists, so return values need not be described, and the schema covers all parameters. However, for an 8-parameter mutation tool gated by an approval mechanism, the description is thin and does not surface the approval requirement or confirm what happens to unspecified fields beyond a single clause.

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 the schema already documents all 8 parameters and the baseline is 3. The description adds one collective insight (only passed fields are modified) but no per-parameter meaning beyond the schema, so it neither over- nor under-delivers.

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 description frames the tool as a condition ('When a saved address changed') rather than stating a clear verb+resource; the actual purpose is carried mostly by the title 'Update Address' and the tool name. The second sentence clarifies it is a partial update, which helps, but the purpose statement itself is weak and does not differentiate from siblings beyond what their names already imply.

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 only usage signal is the trigger 'When a saved address changed', which gives minimal context but names no alternatives. There is no guidance on when to use this versus addresses.create (to add a new one) or addresses.delete (to remove one), nor any prerequisites.

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