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

Annotations cover the safety profile (readOnly, idempotent, openWorld), so the bar is lower. The description still adds two behavioral facts beyond the schema: results are sorted 'newest filing first', and ticker-or-cik is a hard requirement despite the schema listing no required fields. No pagination or return-shape detail, but the ordering and constraint disclosure are substantive.

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 tightly written sentences: the first identifies the resource, examples, scope and sort order; the second states the input constraint. Nothing is padded and the identity of the tool is front-loaded.

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?

With no output schema, the description should carry return-value burden, and it partially does by disclosing sort order and pagination-nullable cursor plus the ticker/cik requirement. It stops short of describing what a result record contains, but for a read-only list tool with full schema coverage this is close to complete.

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 every parameter (to, from, cik, limit, cursor, ticker, event_type) is already fully documented in the schema. The description adds only framing context ('SEC Form 8-K') and no syntax or semantic detail beyond the schema, 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 verb and resource ('Searches material events (SEC Form 8-K)') with concrete examples of event categories and a scope qualifier ('of one company'). It differentiates from events_get by being a search/list, but does not explicitly distinguish itself from events_list_recent, which shares nearly identical framing.

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 gives one precondition — 'Either ticker or cik is required' — which is genuine usage guidance since the schema marks zero required parameters. However, it never says when to pick this tool over the sibling events_list_recent or events_get, so the agent must infer the choice.

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