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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, non-open-world), and the description adds domain behavior they cannot: access-gating (only consenting people appear), the wait-time and asked/accepted state per errand, and the semantics of an empty 'items' array vs. a populated one. That is real operational context beyond 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?

Front-loaded with the core purpose, then the access caveat and the 'items' handling rule, then examples. Dense but every sentence carries information; the mid-clause parenthetical about 'Groceries' is slightly verbose but clarifies the items rule usefully.

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 structure need not be described, and annotations cover the safety profile. The description is complete on scope, consent filtering, and item semantics; the main remaining gap is that it never routes to a sibling for adjacent needs.

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 both 'person' and 'category' are already documented in the schema. The example queries demonstrate filtering by person ('what has Mom asked for') but do not add syntax, matching rules, or format detail beyond the schema, so baseline 3 applies.

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 retrieval: open errands and list items belonging to other people in the connected person's Circle, scoped to those who enabled assistant access. This clearly separates it from siblings like my_list (the caller's own list) and add_errand (a write). The verb+resource+scope are all present.

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 explicit trigger phrases ('what does everyone need', 'what has Mom asked for', 'did anyone already get the milk') and states an exclusion ('People who did not turn on access do not appear'). It never names an alternative sibling to redirect to, so it falls short of full when/when-not routing.

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