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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is covered structurally. The description adds one genuinely useful operational fact — it costs 1 credit — but says nothing about result volume, whether the history is paginated, or how 'limit' truncates older filings.

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?

A single front-loaded sentence naming the resource and its contents, with the credit cost appended. No filler or redundancy, though the parenthetical list plus cost note in one sentence is slightly dense.

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?

A two-parameter read tool with full annotations and no output schema, so the description needn't explain return values. Still, it omits ordering (newest first?), pagination behavior, and any note that limit caps result size — details an agent would want before calling with a truncated limit.

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 description coverage is 100%, so both parameters are already documented ('number 1-100' and 'string, required'). The description only implies that companyNumber is a company number; it adds no meaning about what limit counts (filings vs pages) or default behavior when omitted, so the 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 resource ('Filing history') and scope ('for a company number') plus concrete categories enumerated in parentheses (accounts, confirmation statements, officer changes, charges). An agent can tell this returns a company's filed-document history, but nothing in the text separates it from siblings like company_profile, company_officers, or company_pscs, which likely overlap.

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?

No explicit when-to-use or when-not-to-use guidance and no named alternative. The agent must infer from the parenthetical categories whether to call this rather than company_officers (for officers) or company_profile (for company overview), which is a real ambiguity given the sibling list.

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