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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description nonetheless adds real behavioral detail beyond them: newest-first ordering, a 20-item page size, and the null-when-exhausted semantics of nextCursor. It does not mention auth or rate limits, keeping it short of a 5.

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?

Purpose and payload are front-loaded in the first clause, then pagination, then the disclaimer. The opening sentence is long and densely packed with clauses, but each clause carries information an agent needs; the closing disclaimer sentence is arguably optional but short.

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 description carries the full burden of describing the return value and does so: posts with sentiment, excerpt, source, author track record, ordering, page size, and nextCursor semantics. Nothing needed to call it correctly is missing.

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 both 'id' and 'cursor' are already documented in the schema with the same meaning. The description reinforces that cursor retrieves older posts and that nextCursor is its source, but adds no syntax or format detail beyond the schema. 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?

States a specific verb and resource ('Returns one story by its id') plus the payload it carries ('the posts and filings behind it'). The singular 'one story by its id' cleanly distinguishes it from the sibling get_stories list tool without the agent needing to open either schema.

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 phrase 'by its id' implies this is the lookup path once you already have a story id, and the cursor sentence implies the follow-up call for older posts. However, it never explicitly contrasts with get_stories or states when not to use it, so the routing is left to inference.

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