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

Adds substantial context beyond the annotations: per-call cost, no charge when nothing matches, return fields per province, licence/attribution line on every answer, and the explicit 'no images' constraint. These are exactly the operational facts an agent needs before paying for a call.

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?

Dense but front-loaded: cost and scope first, then modes, then return contents and caveats. Every sentence carries information, though the single long paragraph could be split for easier scanning.

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?

There is no output schema, so the description must explain returns, and it does: id, coordinates, type, condition, assessment date where published, plus licence/attribution and the no-image caveat. For a 7-parameter nested-schema read tool, nothing an agent needs in order to call it correctly is missing.

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 semantic value: nearest-search ordering, the 25-item cap with distance included, and the fact that every result carries an MGRS 10-figure reference. It does not restate the mode-exclusivity constraints, which the schema already handles.

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 ('look up survey control monuments'), names the three covered provinces (NS, BC, NL), and enumerates the three lookup modes. An agent can distinguish this from unrelated siblings immediately, and the MGRS detail ties it loosely to convert_mgrs without ambiguity.

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?

Clearly enumerates the three selection paths (monument id, bounding box, nearest to lat/lon) and the 25-result nearest-first behaviour, which tells an agent which mode to pick for which question. It does not name sibling alternatives or exclusions (e.g., when to use convert_mgrs instead), which is why it stops short of 5.

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