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

While readOnlyHint is already true, the description adds useful behavioral context by stating 'Keeps the ownership math server-side' and 'fully-diluted source roster.' This clarifies that calculations are authoritative and server-computed, going beyond the annotation alone.

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 three sentences, front-loaded with the core purpose and details, followed by a short note on computation location and read-only status. Every sentence adds value and there is no filler.

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 description adequately covers the return content and adds the server-side computation context, and an output schema exists to detail return fields. However, it omits the effect of the optional 'asOf' parameter and gives no guidance on how this tool relates to similar siblings like overview or round summaries, leaving some contextual gaps.

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?

The description does not explain the 'asOf' parameter or its effect on the aggregation. The schema provides only a weak description for companyId ('UUID value wrapper') and no description for asOf. With 50% schema coverage, the description needed to compensate but did not, leaving parameter meanings partially ambiguous.

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 returns a dashboard aggregate with specific metrics (totals, stakeholder count, founders %, per-type ownership segments) on the fully-diluted source roster. This is a specific verb+resource and delineates its function from other cap-table tools like overview or round summaries.

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 mentions 'Keeps the ownership math server-side,' implying the tool should be used when you need pre-computed ownership calculations rather than doing the math yourself. However, it does not explicitly state when to use this tool versus alternatives like cap_table_get_cap_table_overview, nor does it provide exclusions.

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