findUniqRecord

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful behavior beyond that: the tool throws on zero matches and on multiple matches, which is the key distinction an agent must know before calling it. It does not cover return shape, but an output schema exists.

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?

Three sentences with no filler, front-loaded with the core behavior and the throw semantics, then the use case, then the alternative. Every sentence earns its place.

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 two-parameter read lookup with an output schema, annotations, and a 100%-covered input schema, nothing an agent needs is missing. The distinctive error behavior and the sibling routing are both spelled out.

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% and both parameters (where, labels) are documented in the schema, so the baseline is 3. The description mentions example key types (email, code, slug) for uniqueness but adds no syntax or format detail for the where/labels parameters themselves.

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 (return the single unique record) plus the exact scope constraint: it throws when zero or more than one record matches. It is immediately distinguishable from findRecords, findOneRecord, and getRecord by that all-or-nothing semantics.

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?

Explicitly says when to use it (unique-key lookups like email, code, slug where exactly one result is expected) and names the alternative with the condition that selects it: use findOneRecord when only the first match is wanted and duplicates are acceptable. Both the when and the when-not are covered.

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