entity_lookupThe Asbestos Survey Cost register entry for a firm, by its register identifier (scheme + value, e.g. lei) or by the slug of its page. Exact match; returns the whole record with its page.
| Name | Required | Description | Default |
|---|---|---|---|
| slug | No | ||
| value | No | ||
| scheme | No | identifier scheme, e.g. lei, fca_frn, tdlr_license |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are supplied, so the description carries the full burden. It does disclose the key behavior that matters here: matching is exact, and the return is the whole record with its page. It omits not-found behaviour, whether slug and scheme+value are alternative selectors or combined, and any auth or rate-limit context.
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?
One dense, front-loaded sentence: resource first, then the two lookup paths, then the matching semantics and return shape. No filler and nothing repeated from the schema.
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?
With no output schema, the description helpfully states it returns the whole record plus its page, covering the return value. But for a tool with three parameters and zero required fields, it leaves the selector logic (slug vs scheme+value), failure behaviour, and any access constraints unaddressed.
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 only 33% (only 'scheme' is documented inline), so the description must compensate. It explains the scheme+value pairing and gives an example ('lei') matching the schema's own examples, and identifies slug as a page-slug alternative. It does not clarify the mutual exclusivity or the required combination of these two selector paths, leaving ambiguity for a 0-required-param tool.
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: retrieve one register entry ('a firm') either by register identifier (scheme + value) or by page slug. It is distinguishable from the sibling entities_search because it explicitly says 'Exact match', implying search is the fuzzy alternative. It stops short of naming that sibling outright, so it is clear but not fully differentiated.
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 phrase 'Exact match' implicitly tells the agent to use this tool when it holds a precise identifier rather than a query string, which is useful implied guidance. However, it never states when NOT to use it, names no alternative (entities_search, entities_in, entities_export), and says nothing about what happens on a miss or whether slug and scheme/value are mutually exclusive.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.