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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuine data-quality context the annotations cannot: amounts are null when undisclosed and 'never estimated', and each round carries its evidence trail and source link.

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 a single dense sentence that front-loads scope and ordering before the field list, with no filler. Slightly long, but each clause (null handling, evidence, source link) carries distinct information.

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 compensates by enumerating the returned fields (amount, stage, investors, evidence, source link) and the sort order, plus the null-amount rule. A reader can predict the response shape; only pagination/total-count behavior is left unspecified.

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 schema already documents days, limit, stage, company, and min_amount_usd with ranges and matching semantics. The description adds only the placeholder/never-estimate rule for undisclosed amounts, which is marginal extra meaning over the schema 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 the exact resource (closed private funding rounds into space companies), the scope (last 90 days), and the ordering (newest first), which cleanly separates it from the sibling funding_round_history that covers older/all rounds. An agent can identify what it returns without opening the 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?

Usage is implied by the 90-day window and the sibling set, but the description never states when to pick this over funding_round_history or company_lookup, and lists no exclusions. It is adequate but leaves routing to inference.

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