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

Annotations already declare readOnlyHint=true, so the read-only nature is covered. The description adds useful behavioral context by explaining the index calculation (7-day vs 28-day baseline), keyless SEC EDGAR search, history to 2001, and daily updates, which go beyond the annotations.

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 dense sentence with parenthetical methodologies and output fields, followed by a usage sentence and 'Updates: daily.' It is efficient with no wasted words, but the main sentence is overloaded and could be better structured for readability.

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 lists the return fields (score, form_mix, s1_pipeline_count, drivers, methodology_version), the optional history parameter, and update frequency. It could define the fields in more detail, but for a read-only index tool, this is adequate.

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% and the sole parameter 'days' has a rich description in the schema, including the optional history series and Gold tier restriction. The tool description itself adds no parameter details, so the baseline score of 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?

The description clearly states a specific verb ('Returns') and resource ('daily 0-100 US corporate disclosure-velocity index') with methodology, output fields, and history. It distinguishes itself through its unique focus on SEC filing activity and 8-K surges, even without explicitly naming sibling alternatives.

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 lists when to call the tool ('when the user asks about SEC filing activity, 8-K surges...' etc.), providing clear context and use cases. However, it does not mention when not to use it or name alternative tools, falling short of full exclusion guidance.

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