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

Beyond the annotations (readOnly, idempotent, openWorld), the description discloses the credit cost of a successful call, the 404 behavior for stale/unknown IDs, ID-to-index-snapshot coupling, and a data caveat about unverified floor/unit suffixes. These are exactly the non-obvious runtime traits annotations cannot express, and they do not contradict readOnlyHint.

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?

The credit cost is stated twice in nearly identical words ('costs one credit' / 'consumes one account credit'), and the index-update advice is split from the staleness statement. Front-loading is reasonable but a sentence is wasted.

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 one-parameter read tool this covers prerequisites, cost, error behavior, and a data caveat. The remaining gap is that with no output schema the description never says what fields the retrieved record returns, leaving only the passing mention of 'the retrieved building'.

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% and the single parameter is already documented as opaque, so the baseline is 3. The description earns one more point by explaining the ID's lifetime semantics — tied to an index snapshot, invalidated by index updates, 404 on staleness — which the schema does not say.

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 states a specific action (fetch the full record for the autocomplete suggestion the user picked) and ties it to the autocomplete sibling, which is referenced again in the index-snapshot note. The object returned is only obliquely implied by 'the retrieved building', so it stays short of a fully crisp verb+resource statement.

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 workflow prerequisite is clear — an ID comes from autocomplete and must be re-requested after an index update — and the failure condition (stale or unknown ID returns 404) is given. There is no explicit 'when not to use this / use search or reverse instead' exclusion against the other siblings.

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