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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so 'Read-only' in the description earns no credit as a repeat. The description does add real behavioral substance beyond that: it defines the freshness rule (under twelve months old and no closed priced round) and the consequence of stale status, which is the fact an agent most needs before acting.

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?

It is front-loaded with the resource and every clause is informative, but the single run-on field list is dense and the parenthetical 'under twelve months old and older than no closed priced round' is grammatically garbled enough to slow comprehension. Splitting the freshness rule into its own sentence would cost nothing and gain clarity.

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?

For a one-parameter read tool with an output schema and full annotation coverage, the description is nearly complete: it explains the currency semantics and the operational consequence of an expired valuation. Since an output schema exists, the field enumeration is partly redundant but is defensible as domain framing. Only the absence of any alternative-routing guidance leaves a small gap.

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?

There is a single required companyId with 100% schema description coverage, so the schema carries the parameter burden and the baseline is 3. The description adds no scoping, ownership, or access meaning about that identifier (e.g., whether it can be a non-member company), so it does not exceed baseline.

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 names a specific domain resource (the company's 409A status) and enumerates exactly what it reports: latest common-stock valuation, currency state, expiry day and reason, minimum exercise price, and 409A orders. An agent can distinguish it from sibling reads like equity_get_qsbs_log or cap_table_get_cap_table_health. It never states the verb explicitly and does not name a nearest alternative, which keeps it off a 5.

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?

There is one concrete downstream rule — 'No option may be proposed when current is false' — which effectively tells the agent to check this before proposing a grant. Beyond that, there is no explicit when-to-use/when-not guidance and no sibling alternative is named, so the usage signal is implied rather than spelled out.

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