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

Annotations already declare readOnly/idempotent/non-destructive, and the description still adds substantial behavior: plan gating, currency of amounts, excluded records (sold stock, fund and SPV interests), and explicitly what is NOT reported (exercise cost, side-letter caps/termination terms). This is disclosure well beyond the structured fields.

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 purpose and behaviorally dense throughout, but it is a long paragraph for a three-parameter list tool and a few clauses ('a round nobody can see yet') are stylistic filler. Nearly every sentence still carries signal, so the size is defensible.

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 carries the return-shape burden and does so: one entry per position, the granting side letter, the ownership it defends, and currency. Exclusions and gating are also covered, leaving no material gap for correct invocation.

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 the baseline is 3; the description still adds meaning to the `company` parameter by explaining that scoping to a slug keeps it available on any plan, which the schema does not convey. Page/per_page are left to the schema.

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+resource (pro rata rights in the authenticated user's portfolio), defines the concept, and specifies ordering ('largest position first'). No sibling lists pro rata rights, so the agent can route to it unambiguously.

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 concrete when-to-use framing ('where the user can follow on', 'which side letters to go find when a round is announced') and a prerequisite: scoping by company slug works on any plan while a full-portfolio sweep needs the Investor plan. It stops short of naming exclusionary cases or alternatives, but there is no competing sibling to route against.

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