substack_leaderboard

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

With no annotations, the description carries the transparency burden and does well: it discloses pagination behavior (25 rows per page, pages 0-25), the validation trait ('validates its ranking values rather than silently defaulting'), and the returned pairing. It does not discuss errors or authentication, but the read-only nature and pagination are covered.

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?

Four sentences with no filler. The core purpose is front-loaded, and each subsequent sentence adds a distinct piece of operational knowledge: return shape, differentiation from a sibling, prerequisite, and pagination limits.

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 simple read tool with no output schema and no annotations, the description supplies everything needed to call it correctly: what it returns, how it differs from the sibling, which category ids are valid, and pagination bounds. There is no material gap for an agent deciding whether and how to invoke it.

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 baseline is 3, but the description adds meaningful context: category_id must come from /substack/categories with in_leaderboard true, the special 'bestseller' id is allowed, and page has an upstream 0-25 bound reflecting 25-row pages. This goes beyond the raw schema.

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 a specific verb ('List'), resource ('a Substack category's bestseller leaderboard'), and return content ('pairing each ranked publication with its author'). It explicitly contrasts itself with /substack/category, so an agent can distinguish it from the sibling substack_category without inspecting schemas.

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 states the exact prerequisite: use a category_id from /substack/categories where in_leaderboard is true. It also names the alternative surface (/substack/category) and explains the key differences—trending ranking, validation behavior, extra bestseller id, and author inclusion—so the agent knows when this tool is the right choice.

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