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

Annotations already declare readOnlyHint=true, openWorldHint=true, and idempotentHint=true, so the safety profile is covered. The description adds valuable behavioral context: it explains DST ambiguity handling, the 'time_assumed_noon' flag, the 'local_time_ambiguity' field, and that nothing is stored server-side. It doesn't fully explain what happens in ambiguous/nonexistent cases beyond 'ask the user', but the disclosure is strong.

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 description is dense but well-organized, front-loading the most important usage instruction ('Call this FIRST'). It packs a lot of information into a few sentences, though the list of return fields is long and could be slightly more scannable. Every sentence earns its place.

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 tool with 2 parameters, 100% schema coverage, and no output schema, the description is remarkably complete. It explains the return fields, the ambiguity flags, the noon assumption, the historical timezone handling, and the privacy behavior. An agent has everything it needs to call this tool correctly and interpret its output.

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 the schema already documents both parameters well. The description adds meaning by explaining that local_datetime must be in LOCAL time without an offset, and that 'YYYY-MM-DD' alone triggers noon assumption. It also clarifies that the place can be in any language. This goes beyond the schema's basic descriptions.

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 verb ('resolve') and resource ('birth place'), and clearly distinguishes this tool from siblings by naming the downstream tools it feeds. It also explicitly says to call it FIRST whenever birth data appears, which differentiates it from calculate_natal_chart, get_transits_and_aspects, and calculate_synastry.

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 description gives explicit when-to-use guidance ('Call this FIRST whenever a birth date / time and a place of birth appear in the conversation'), and explicit when-not-to-use guidance ('Never compute coordinates, timezones or UTC offsets yourself and never web-search them'). It also names the downstream tools that consume its output, making the workflow clear.

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