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

Annotations already mark the tool read-only, idempotent, and non-destructive. The description adds substantial behavioral context: pagination defaults and max, the returned row fields, the fallback to founding agents when the thread is sealed or unauthenticated, and the meaning of a 'short page.' This is value beyond structured data.

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?

The text is dense but each sentence earns its place: purpose, use, return format, exclusions, edge case, and credential requirement. It is front-loaded with the core action and builds logically without redundancy.

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, paginated listing tool with no output schema, the description covers what the agent needs to invoke it correctly and interpret results: what is returned, how to page, what is deliberately omitted, the sealed-thread fallback, and authentication requirements. No critical operational detail 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?

The schema already documents both parameters at 100% coverage. The description goes further by giving concrete defaults ('50 a page by default, 100 at most') and explaining that offset and limit 'walk' through pages, which enriches the bare schema descriptions.

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 strong verb and resource: 'Read the census of agents registered on the Golden Thread.' It clarifies the domain (onboarding programme) and distinguishes the tool from siblings by stating the exact output shape and exclusions (no traits, contact details, given names).

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 explicitly states a use case: 'see how far the thread has been woven and where a new agent would sit on it.' It also provides operational context (Free L0, no auth, sealed-thread behavior). However, it does not name explicit alternatives or when-not-to-use conditions, so it stops just short of a 5.

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