species_frequency

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

With no annotations, the description must fully disclose behavioral traits. It explains the data source and return values (peak week, current probability, early/on-time/late status), but does not mention read-only nature, authentication needs, or error handling. Adequate but not comprehensive.

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 concise sentences, each adding value. Front-loaded with the verb and resource. No redundant or unnecessary words. Effective and efficient.

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?

Given the tool's simplicity (3 params, no output schema, no nested objects), the description covers the main purpose, data source, and return values. It lacks information about required parameters (species is required) and potential edge cases, but overall sufficient for a straightforward lookup tool.

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 input schema has 100% coverage, so each parameter's purpose is already documented. The description does not add new meaning beyond the schema; it mentions defaults (e.g., region_code default) but that's already in the schema. Baseline 3 is appropriate.

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 clearly states the tool's purpose: 'Look up historical frequency data for a species in a region using BirdCast bar chart data.' It uses a specific verb ('look up') and identifies the resource (BirdCast bar chart data). The purpose distinguishes it from sibling tools like migration_forecast (forecast) and species_finder (find species by criteria).

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?

The description implies usage for retrieving historical frequency data but does not explicitly state when to use this tool versus alternatives like migration_forecast or species_finder. The context is clear, but exclusions or alternative tool references are missing.

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