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

readOnlyHint=true already tells the agent this is a safe read, so the description only needs to add context. It does contribute the underlying API call (GET /{account}/zones/{zone}/records/{record}), which corroborates the read-only nature and shows the resource hierarchy, but it says nothing about 404 behavior for unknown ids or rate limits.

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?

Two short sentences, front-loaded with the verb and the identifying key, with zero redundant or filler text. The API endpoint is appended compactly rather than as a separate paragraph.

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?

A two-parameter read tool with full annotation coverage needs little, and the description covers the addressing model. However, with no output schema, it could have indicated what the returned record contains or how it differs from a list entry; that omission leaves a modest gap.

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 both parameters ('zone' as zone name, 'record' as numeric id) are already fully documented. The description restates the same addressing ('in a zone by its numeric id') without adding format examples or constraints, so baseline 3 applies.

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 a single DNS record in a zone') plus the addressing key ('by its numeric id'), which cleanly separates it from the plural dnsimple_list_zone_records sibling. It stops short of naming that sibling explicitly, so the differentiation is implied rather than stated.

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 implied by the phrasing (fetch one record when you already have its numeric id), but there is no explicit when-to-use clause, no exclusion, and no pointer to dnsimple_list_zone_records for discovery or to the create/update/delete siblings for mutation. Nothing misleading, but nothing that actively routes the agent.

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