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

Annotations already declare it as a non-read-only, non-destructive, non-idempotent write, and the description stays consistent with that while adding genuine value: the partial-update/preserve-untouched-fields contract and the returned shape { ideaId, updatedFields, setup, briefReady }. It does not mention auth or what happens to invalid enum values, so it stops short of full disclosure.

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?

Well front-loaded: mutation semantics first, sequencing second, then Args, constraints, and Returns. The argument list is long but each item is necessary given the 0% schema coverage; the only waste is that listing bare field names adds little for the ambiguous ones.

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 16-parameter mutation with no output schema and no annotation nuance beyond the hints, the definition covers the return shape, the partial-update contract, the enum domains, and the upstream dependency. It lacks a description of what several fields mean, which is the remaining 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?

Schema description coverage is 0% across 16 parameters, so the description carries the burden, and it does contribute the enum constraints (primaryMarket in US/CA/GB/AU/GL; conversionMode in waitlist/external_url) plus the at-least-one-required rule. However, it only enumerates the other 14 field names without explaining what any of them mean, and it omits response_format entirely, so the compensation is partial.

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 precise verb+resource ('Save one or more brief fields on an idea') and immediately qualifies the semantics with 'Only the fields you pass are changed; the rest are preserved.' This distinguishes it cleanly from idealaunch_create_idea and idealaunch_draft_brief without requiring the schema to be opened.

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?

Explicitly sequences the tool: 'Use this after idealaunch_draft_brief, once the founder has approved the wording.' It names the upstream sibling and the human-approval precondition, so an agent knows both ordering and gating.

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