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

Goes well beyond the annotations: never exposes the real address or substrings, resolves orders server-side, requires human Passkey confirmation in the PWA before any write, submitted address is write-only and never echoed, and one active request per account with explicit idempotent-reuse vs conflict semantics. This is exactly the mutation-safety context an agent needs.

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?

Front-loaded with a clear statement and organized as per-action bullets, so an agent can scan it quickly. The '(RFC-026 PR-5, safe scopes address_read_masked / address_change_request under the address scope)' parenthetical is internal reference material that does little for tool selection and slightly bloats the opening.

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?

No output schema exists, yet the description enumerates the masked_read return fields ({ has_default, address_region, masked_summary }) and fully describes the change_request outcome path including conflict behavior. Nothing needed to invoke either action correctly 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 coverage is already 100%, but the description still adds value: it restates address_text length bounds and write-only nature, the 2-letter region requirement, and the idempotency/conflict behavior tied to repeated submissions. That goes past the schema's per-parameter blurbs.

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 names both the resource (default shipping address) and the two distinct operations precisely: a masked read and a Passkey-gated change request. The action bullets make the split unambiguous. It stops short of differentiating itself from the sibling webaz_default_address, which sounds closely related, so it is clear but not sibling-aware.

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?

Each action has an explicit use case: masked_read for status, change_request to file a human-confirmed change. It adds a hard rule ('Only submit an address the human explicitly gave you in this conversation — never fabricate or guess one') that meaningfully constrains behavior. It does not mention when to prefer a sibling tool over this one.

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