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

With no annotations, the description discloses key behavioral traits: endpoints are inclusive, results are grouped by section, and there's a hard maximum of 500 beyts. It also clarifies the two endpoint formats (canonical citations vs global indices), providing useful context beyond the bare schema.

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, each with a distinct purpose: action, usage guidance, endpoint format, and limit. No filler or repetition.

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 read-only fetch tool with an output schema, the description covers the essential usage and constraints. It could mention error handling for exceeding the range, but the given info (grouping, inclusivity, max range) is sufficient for most agent calls. The sibling list context further clarifies its role.

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 descriptions cover start and end with examples, but start_global and end_global have no schema descriptions (50% coverage). The description partially compensates by naming them as 'global indices' and connecting them to the endpoint concept, but it doesn't disallow mixing endpoint types or specify parameter relationships (e.g., start must precede end). This leaves some semantic ambiguity.

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 opens with a precise action: 'Fetch ALL beyts between two endpoints, inclusive, grouped by section.' It distinguishes itself from siblings by explicitly positioning against get_section and lookup, making its unique scope clear.

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?

Explicit guidance is given: 'Use this — NOT many calls to get_section or lookup — when a user asks for a full story, a long passage, or a sequence of beyts spanning multiple sections.' This states the when and the alternatives clearly.

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