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

Annotations already signal mutability (destructiveHint=true), so the bar is lower. The description adds valuable behavioral context: no source quota is consumed, estimates are unverified until bytes arrive, and specific retry/idempotency behaviors. It does not contradict annotations; it supplements them with operational details relevant to an agent.

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?

The description is dense but every sentence contributes: purpose, quota behavior, workflow, and error handling. It is not overly verbose for the amount of information packed, though the multiple clauses in later sentences could be slightly restructured for readability.

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?

No output schema exists, so the description should clarify what the tool returns or how to interpret results; it does not. It provides strong workflow guidance but leaves ambiguity about whether the tool itself transfers files or whether that is a separate step. For an agent, the lack of explicit return-value information and the ambiguous 'transfer' phrasing create a 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 coverage is 67% (projectId and idempotencyKey have descriptions; manifest does not). The description hints that manifest represents 'actual selected files' and implies a list of items, but it does not explain the nested structure or enums. This adds marginal meaning beyond the schema but does not fully compensate for the manifest's lack of schema description.

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 opens with 'Preview actual selected files for free', which is a clear verb+resource statement. It also distinguishes the tool by noting 'No source quota is consumed', setting it apart from upload/import tools. However, it does not explicitly differentiate from sibling tools like helvabase_upload_sources, leaving some ambiguity about where preview ends and transfer begins.

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 explicit workflow guidance: review exact selection with the user, transfer in batches of at most 20 files, keep confirmed receipts, retry only failed files, and inspect pending imports before replaying. This tells the agent when and how to use the tool effectively. It does not explicitly name alternative tools, but the context strongly implies it is a pre-transfer verification step.

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