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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds valuable behavioral context: it severity-ranks results, drops noise/procedural filings by default, and defaults to high+medium severity. This goes beyond the structured annotations and helps the agent understand the tool's filtering logic.

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 core purpose, followed by filtering behavior and use cases. Every word earns its place—no fluff or repetition of schema content.

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 simple read-only tool with two optional parameters and no output schema, the description is complete. It explains what it does, how it filters, and when to use it. The only minor omission is the exact return format, but that is not needed given the simplicity and annotations.

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 (limit, severity) are fully described in the schema. The description mentions severity ranking and default filtering, but this reinforces rather than extends the schema details. Baseline 3 is appropriate given the high coverage.

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 lists 8-K material events filed today or the most recent trading session, severity-ranked. The verb 'filed' and resource '8-K material events' are specific, and the timeframe is explicit, distinguishing it from siblings like sec_8k_recent and sec_8k_by_item.

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 clear use cases ('what mattered in the market today?' / 'any breaking corporate news?') and explains the default filtering behavior. However, it does not explicitly name alternative tools or scenarios to avoid, unlike a perfect score that would include when-not-to-use guidance.

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