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

Annotations only flag destructiveHint/not-idempotent; the description goes well beyond them by disclosing partial-update semantics ('Only the provided fields are changed'), the in-use read-only lock with its one exception (blank address_area), and the empty-string clear behavior. These are non-obvious mutation side effects an agent cannot infer from structured fields.

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?

Dense and front-loaded — the mutability scope and the create_address alternative come before the edge cases. Minor waste in the parenthetical '(same as the panel)', which carries little actionable meaning for an agent.

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 5-param, no-output-schema mutation tool, the description supplies everything an agent needs: which params are editable, the irreversible/in-use constraint, the clearing convention, and the fallback tool. No return-value explanation is required since there is no output schema.

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 100%, so the baseline is 3, but the description adds meaning the schema does not carry: the immutable-field rule (country/city/identity can never change) and the condition under which provided fields are rejected. Field-clearing is partly duplicated from the schema's own 'Empty string clears it' note.

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+resource ('Update an existing regulation address of the authenticated customer') and immediately scopes which fields are mutable versus immutable. An agent can distinguish it from create_address, delete_address and list_addresses without opening any schema.

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?

Names the alternative explicitly — 'for a different location create a new address with create_address' — and gives the conditions under which fields can no longer be edited (address in use/linked to DIDs or verifications). It also tells the agent to check list_addresses for the address_id, giving a concrete prerequisite path.

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