search_places_at_date

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

With readOnlyHint and openWorldHint already declared, the description still earns credit by adding auth context ('Works without credentials') and by describing the shape of results ('Each result carries the span over which that jurisdiction existed'), which matters because no output schema exists. It stops short of saying how many results to expect or how ambiguity is signalled beyond the within_place_id hint.

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 core operation is front-loaded in the first sentence, and the remaining paragraphs are rationale rather than filler — they explain the failure mode the tool guards against. It is a touch discursive at roughly 140 words for a four-parameter lookup, but nothing is purely decorative.

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 read-only, open-world lookup with full schema coverage and no output schema, the description covers the essentials: what is resolved, which inputs matter and in what form, that no credentials are needed, and what each result contains. An agent has everything required to invoke it correctly.

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%, including the important 'use the year of the record, not today' note on year and the narrowing role of within_place_id, so the baseline of 3 applies. The prose reinforces the name/year convention but adds no syntax, format, or edge-case detail beyond what the schema already carries.

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 opening sentence gives a specific verb (resolve), resource (place), and a temporal scope (as it existed in a particular year) that cleanly separates it from the modern-place siblings search_places and get_place. However, it never names those siblings, so the agent has to infer the routing distinction rather than being told.

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?

It gives concrete operating guidance: pass the name as the record spells it, use the year of the record rather than today, and avoid filing an old record under the modern county. That is clear when-to-use context, but it stops short of explicitly naming an alternative tool for modern-name lookups, so there is no true when-not.

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