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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description's added value is disclosing the shape of the result: it compares pricing and returns features/integrations/platforms marked as shared or unique to one app. That return-content disclosure is meaningful, especially with no output schema; it stops short of noting behavior for unknown or ambiguous app names.

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 sentence with zero filler, and the comparison dimensions are front-loaded. The grammar is slightly compressed ("the features, integrations and platforms both apps have or only one has"), but no sentence is wasted.

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 only two required string params, rich annotations, and no output schema, the main missing piece was return content — and the description supplies the comparison axes and the shared/unique framing. Only edge-case behavior (nonexistent app, ambiguous name, differing result granularity) is left 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 100% — both 'first' and 'second' are documented as 'app name or slug' with length bounds — so the schema carries parameter meaning. The description adds no resolution guidance (e.g. what happens if a slug is ambiguous or an app is missing), 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?

The description names the operation (side-by-side comparison) and enumerates the compared dimensions — pricing, features, integrations, platforms — plus the shared-vs-unique distinction. That clearly separates it from get_app (single app) and find_alternatives. The verb is elided in a fragment ("Side by side:"), relying on name/title to supply 'compare', so it falls short of a fully explicit verb+resource statement.

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?

There is no statement of when to use this versus get_app, find_alternatives, or recommend_apps, and no prerequisites such as both apps needing to exist in the catalog. The use case is inferable from the name alone, but nothing in the text 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.