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

readOnlyHint=true already tells the agent this is a safe read. The description adds genuine value by saying the response includes the record's 'latest recorded fact', giving a hint of return shape. It does not say whether a missing id errors or returns empty, nor whether lookup is exact-match only.

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?

A single compact sentence with the key information front-loaded and no filler. The tradeoff is that it is a noun phrase rather than a sentence, which slightly reduces scannability.

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 one-parameter read tool with no output schema, the definition covers the resource, the accepted identifier namespaces, and what the response contains. Remaining unknowns (error behavior, exactness of matching) are minor for a simple lookup.

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?

With one parameter and 0% schema description coverage, the description carries the burden and does so reasonably: it enumerates the accepted id forms (rec_ ids and the mcp:/npm:/pypi: source-id patterns) that the bare 'string' type does not express. It stops short of examples or format validation rules.

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 names the resource (one record) and the retrieval key forms (rec_ id, or source ids like mcp:<registry>, npm:<name>, pypi:<name>), which separates it from record_search (query-based) and record_versions (history). It lacks an explicit verb ('Get' only appears in the title) and never names the siblings, so it falls short of a 5.

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?

Usage is only implied: the id-keyed phrasing implies 'use this when you already have an exact identifier, otherwise search.' There is no explicit statement of when to prefer record_search or record_versions, and no note about what happens on a miss.

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