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

Annotations only declare openWorldHint=false and destructiveHint=false, so the description carries the real behavioral load and does it well: the new round starts OPEN and holds no capital, past rounds are marked recorded and never re-priced, and the recorded flag is server-set and ignored on input. The write semantics ("Writes.") are consistent with destructiveHint=false.

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 purpose, then the write/does-not-do clarification, then the past_round branch. Every sentence carries information, though the phrasing is dense and the final sentence about the recorded flag could be folded into the previous one.

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 described. For a write tool with nested parameters and only safety annotations, the description covers the critical behavioral traps (open vs. recorded, server-set flag, no re-pricing) and omits little an agent needs before calling it.

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 description coverage is 0%, so the description must compensate. It does add genuine meaning for past_round and for price_per_share/post_money_valuation in the historical case, but the required round wrapper (companyId UUID wrapper), the status enum, and the many valuation/share fields are left with no semantic guidance beyond the schema's types.

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 (opens a new funding round on a cap table) and defines what the round is (the container investors and agreements attach to). It also explicitly carves out what it is not — it does not raise money or close anything — which separates it from close_cap_table_round and record_cap_table_investment.

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 gives a clear selection rule for the two modes: default behavior opens a new OPEN round, while setting past_round records a historical round instead. It does not explicitly name sibling alternatives (e.g. import_cap_table or close_cap_table_round) as routing targets, but the when-to-use guidance for its own parameters is unambiguous.

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