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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions the content type (8-K filings) but does not disclose whether the tool is read-only, how it handles pagination (the limit parameter implies a cap), whether it requires date ranges (start/end), or what the response structure looks like. For a data-retrieval tool with no annotation safety profile, this is a significant omission.

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 a single sentence with no wasted words. It front-loads the core purpose ('US corporate actions (8-K)') and then lists examples, which is efficient. However, given the tool's complexity (5 parameters, no annotations, no output schema), the brevity becomes under-specification rather than conciseness, but the sentence itself is well-structured and earns its place.

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?

The tool has 5 parameters, no output schema, no annotations, and numerous closely related siblings. The description covers only the basic purpose and examples, omitting parameter usage, output format, pagination, and differentiation from siblings. This is highly inadequate for an agent to invoke the tool correctly without further investigation.

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 0%, and the description provides no explanation of any parameters. The five parameters (end, limit, start, ticker, action_type) are not mentioned at all, leaving the agent to guess that start/end are date bounds, limit controls result count, and ticker/action_type filter results. This is a complete failure to compensate for the missing schema descriptions.

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 clearly states the tool retrieves US corporate actions, specifically 8-K filings, and lists examples like M&A, earnings, dividends, splits, and buybacks. This makes the purpose unambiguous and distinguishes it from siblings like get_corporate_actions (which likely covers broader regions) and get_earnings_calendar (focused on earnings). The verb 'get' implies retrieval, and the resource is well-defined.

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 provides no guidance on when to use this tool versus alternatives. It does not mention that it is US-specific, nor does it suggest using get_corporate_actions for non-US actions or get_earnings_calendar for earnings-only queries. There are no exclusions or contextual clues for selecting this tool over similar ones, leaving the agent to infer usage from the name and examples alone.

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