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

Beyond the annotations (readOnlyHint, idempotent, non-destructive), the description adds important behavioral details: it returns only public findings and pages, unknown tokens yield not_found, and it does not trigger a crawl. These are meaningful, non-obvious behaviors that an agent cannot infer from the schema or annotations.

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 description is compact, with four short sentences each carrying distinct information: the action, token source, return scope, error behavior, and lack of side effects. It is front-loaded with the main purpose and contains no filler.

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 single-parameter read-only tool with an output schema and full annotations, the description is complete. It covers prerequisites, return filtering, error semantics, and side-effect negation, so an agent has everything needed to invoke it correctly.

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 covers the token parameter fully with a pattern and description, so the baseline is 3. The description adds provenance by specifying the token comes from a /preview/{token} URL and that it is 32-hexad?character hex, which is genuinely useful beyond the schema's description.

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 states a specific verb and resource, 'Fetch a Foliora preview snapshot the human already started', which clearly distinguishes it from create_preview_link. It also adds 'Does not start a crawl', further disambiguating from the creation sibling.

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 says the snapshot must already be started by the human, establishing when to use it, and it requires a token from /preview/{token} as a prerequisite. It does not explicitly name an alternative like create_preview_link, but the exclusion 'Does not start a crawl' gives clear contextual guidance.

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