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

Annotations only declare non-destructive/non-open-world; the description adds the idempotency rule ('setting the stage a holding already has is accepted and changes nothing'), the 'wired' immutability, the refusal for founders/employees, and the one-stage-at-a-time progression with the signed exception. This is rich behavioral context 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?

Front-loaded with the core action and the sibling exclusion, then the stage rules. It is dense and long, but nearly every sentence carries a distinct behavioral rule, so little is wasted.

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?

An output schema exists, so return values need not be explained. Combined with the annotations and the stage/immutability/eligibility rules, an agent has everything required to call this correctly for a 3-param mutation.

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 67% and pipelineStatus has no enum, so the description carries the semantic load by naming the stage values (committed, sent, signed, wired, awaiting_middleman) and their ordering, plus 'ONE investor's holding' clarifying the security scope. It stops short of naming the companyId/securityId parameters directly.

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 ('Moves ONE investor's holding along the fundraising pipeline') and explicitly contrasts itself with UpdateCapTableSecurity, which is a full replace. An agent can distinguish it from the update/record siblings without opening any schema.

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?

Gives explicit when-to-use (stage change), when-not-to-use (never UpdateCapTableSecurity; never step through 'sent' to reach 'signed'), alternatives for irreversible states (RecordCapTableWire, RecordCapTableRefund), and rules for reverse moves and founders/employees. Nothing is left to inference.

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