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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so safety is covered. The description adds meaningful context beyond them by describing the nature of the corpus (rules, cross-references, edge cases, plain-English advice), which tells the agent what kind of answer to expect. It doesn't state what happens on an unknown page name or how large pages are.

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?

Two sentences, front-loaded with the resource and its scope, then the immediate next action. No filler and nothing redundant.

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 two-parameter read-only tool with full schema coverage and annotations, this is close to sufficient. The remaining gap is that there is no output schema, and the description only obliquely indicates return shape; it also leaves the apparent tension between a shared knowledge base and the per-company 'company' parameter unresolved.

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 parameters are already documented, including the 'index' convention and example page names. The description reinforces the index-first pattern but adds nothing about the 'company' parameter, whose role in a supposedly shared knowledge base is unexplained. Baseline 3 is appropriate.

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?

A specific verb plus resource ('Read a page from Finn's knowledge base') and it characterizes the content precisely: compiled UK/US tax and accounting guidance for company directors. It doesn't differentiate itself from the similarly named siblings search_wiki and read_company_wiki, which is the main ambiguity an agent would face.

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 gives one concrete workflow instruction — call with page="index" first to enumerate pages — which is genuinely useful. But it never says when to use this versus search_wiki, search_company_wiki, read_company_wiki, or get_gov_guidance, so the choice among the retrieval tools 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.