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

Annotations already establish readOnly/openWorld/non-destructive, and the description adds substantial context beyond that: per-entry search_terms are searched individually and merged, locations returns a numeric id rather than an object. These are non-obvious behavioral traits the agent could not infer from annotations.

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?

Header-delimited sections (USE FOR, CRITERIA TYPES, RESPONSE, WORKFLOW) make it skimmable and front-loaded. Despite its length, every block carries decision-relevant information; nothing is padding.

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 no output schema, the RESPONSE block must carry the full burden of describing return shapes, and it does so per criteria type, including the id-vs-object distinction for locations. The WORKFLOW line also places the tool correctly in the larger create_reddit_target_group sequence.

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%, so the 3 baseline is exceeded only if the description adds meaning. It does: it maps each criteria_type to its search_terms requirement and clarifies how multiple search_terms are combined, which the schema alone does not convey.

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+resource ('Get available Reddit targeting criteria and their reference values') and immediately scopes it to target-group creation. It is clearly distinguished from the generic search_target_group_criteria sibling by the 'Reddit' qualifier and the enumerated criteria types.

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?

A dedicated 'USE FOR' block gives explicit trigger phrases ('what Reddit communities match X?', 'find subreddits about Y') and a prerequisite condition ('get valid references before create_reddit_target_group'). The CRITERIA TYPES section tells the agent exactly which enum value selects which behavior.

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