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

Beyond the readOnlyHint and non-destructive annotations, the description discloses important runtime behavior: paginated response for communities/interests/keywords, the exact shape {content: [{externalId, name}], the locations response {countries, states, regions}, and the warning to use the numeric location id rather than the object. This is behavior an agent could not infer from annotations alone.

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?

The description is well structured with clear labeled sections: USE FOR, CRITERIA TYPES, RESPONSE, and WORKFLOW. Every sentence carries operational value, from the use-case examples to the pagination note, with no filler or repetition of annotation data.

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 2 params and no output schema, the description fully compensates: it documents the required search_terms per criteria type, the exact response shapes for each branch, how to use externalId vs numeric id, and how the tool fits into the create_reddit_target_group workflow. An agent has everything needed to invoke it correctly.

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?

The schema already covers the parameters at 100%, including criteria_type enums and the search_terms requirement note. The description adds extra semantics beyond the schema: which response shape each param value yields, that search_terms should be omitted to list all locations, and that the returned numeric id (not the object) is what goes into the LOCATION criterion.

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 states a precise verb ('Get available Reddit targeting criteria') and the resource, plus the purpose: returning externalId + name reference values for target group creation. The USE FOR examples ('what Reddit communities match X?', 'find subreddits about Y') clearly distinguish this as a Reddit lookup tool distinct from generic siblings like search_target_group_criteria and create_reddit_target_group.

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?

It gives explicit usage guidance: use it before create_reddit_target_group, with the workflow 'search_reddit_criteria → build targeting (LOCATION first) → create_reddit_target_group'. It also explains when search_terms is required versus optional per criteria_type, and for locations it says 'omit to list all, which tells the agent exactly when each variant applies.

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