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

With no annotations provided, the description fully carries the behavioral burden and does so admirably. It discloses accuracy standards (cross-checked against an independent gazetteer), honesty about uncertainty (disputed sites name candidates, unlocatable places have no coordinates), and the by_status counts. This is rich, honest, and goes well beyond a typical tool description.

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 efficient, packing meaningful detail into two sentences. The first sentence is a bit dense with stylistic flourishes ('honestly held,' 'planting one flag') but each phrase contributes to the behavioral contract. It is front-loaded with the tool's identity and then immediately provides usage instructions, with no wasted words.

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 a single optional parameter, no annotations, and no output schema, the description covers the essential context: the type of data, accuracy philosophy, edge cases (disputed/unlocatable), and the two modes of operation. It does not specify exact response field details, but that is not critical for the agent to invoke it correctly, and the by_status counts are mentioned.

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?

The input schema only defines an optional 'name' string with no description, so the parameter would be meaningless without elaboration. The description clarifies that 'name' is used to fetch a single place, and omitting it returns all places with counts, giving the agent a complete understanding of the parameter's role and optionality.

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 clearly states the tool serves as 'The Atlas — biblical places with REAL coordinates,' establishing it as a resource for retrieving biblical geographic data. It distinguishes from siblings like 'locate' or 'resolve' by specifying the scope (biblical places) and the key attribute (coordinates), and it conveys the action (pass a name or list all).

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 provides explicit usage context: 'Pass name for one place; else all places with by_status counts.' This tells the agent exactly when to supply the name parameter and what to expect without it. However, it does not explicitly mention alternatives or when NOT to use this tool, so it falls just short of full guidance.

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