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

Annotations already cover the safe-read profile (readOnly, idempotent, non-destructive). The description adds behavioral facts not in structured fields: wait>0 returns at the first match, and a 100-prefix cap applies in that mode even though the schema allows 500 items.

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?

Three sentences, front-loaded with the purpose before the mechanics. Dense but nearly every clause carries information; the 'keep your address book from the server' phrasing is slightly opaque.

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 annotations present and no output schema, the description explains both inputs and the shape of the answer (live records whose hash starts with any prefix). Minor gaps remain around no-match behavior and record format.

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 baseline is 3, but the description adds real meaning: prefix semantics (sha256 hex, matches by hash prefix) and the early-return behavior of wait that the schema's terse 'seconds to wait' does not convey.

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 and resource: find which known keys are live, in one call. The batching scope ('many keys', 'in one call') is clear and implicit differentiates it from the single-key aamio_presence_get, though no sibling is named.

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 implied context for use (checking many keys at once, choosing short prefixes to limit returned data), but never says when to prefer this over aamio_presence_get or aamio_presence_set, and offers no exclusions.

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