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

With no annotations, the description carries the behavioral burden and does a good job: it discloses that results include observed dates and cryptographic proof, that a human-readable page URL is returned, and that unsupported states produce an explicit notice rather than an empty list. It does not mention authentication, rate limits, or failure modes for unresolved names, so it is not a 5, but it adds meaningful behavioral context beyond the 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?

The description is four sentences, front-loaded with the core function, and every sentence earns its place: purpose, motivating use cases, input pattern, output, and coverage caveat. There is no filler or repetition of schema details that are already obvious.

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?

Given no output schema and no annotations, the description covers the key decision factors: what is returned (changes, dates, proof, URL), how to specify the target company, and geographic limitations. It could be slightly more complete by addressing what happens when a messy name resolves ambiguously or when no changes exist for a covered state, but it is sufficient for correct invocation in most cases.

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 the baseline is 3. The description adds value above the schema by clarifying the OR relationship between 'messy name' and 'exact state + state_id', and by indicating that state_id is used together with state. This helps an agent choose the correct parameter combination, which is not fully explicit in the schema properties alone.

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 ('what has actually CHANGED about one company') and goes further by naming concrete questions it answers (registered agent change, status change, rename). It also distinguishes itself from registry lookups and, by emphasizing 'one company' and change history, separates itself from siblings like private_recent_changes without being ambiguous.

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?

The description explicitly frames when to use the tool: when registry lookup cannot answer historical questions. It also gives clear input guidance ('Accepts a messy name or an exact state + state_id') and warns about state coverage. It does not name alternative sibling tools or give explicit 'do not use when' conditions, but the context is clear enough for an agent to route correctly.

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