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

Annotations already establish the write-but-non-destructive, idempotent profile, so the bar is lower. The description still adds value beyond them by disclosing the exact output manifest and the destination directory (NIMBUS_EXPORT_DIR/bids/), which an agent cannot infer from structured fields. It stops short of noting overwrite behavior or permissions, but with idempotentHint=true that gap is modest.

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?

A single front-loaded sentence leads with verb, resource, and output shape. The parenthetical file list is dense but earns its place by specifying the deliverable; there is no filler. Slightly list-heavy but well structured.

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-value documentation is not required, and the description already covers the artifact contents and save location. The remaining gap is sibling disambiguation against bids.export_dataset, which leaves the agent slightly under-informed for selection, but the definition is otherwise complete for a one-parameter export tool.

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 100% and the single parameter already carries its own description pointing back to execution.run. The tool description adds nothing about the parameter beyond what the schema states, so the baseline 3 applies.

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 verb (Export) and resource (an execution's results, delivered as a BIDS-derivative zip) are specific, and the enumerated file manifest makes the artifact concrete. However, it never distinguishes itself from the sibling 'bids.export_dataset', whose name suggests an almost identical operation, so an agent cannot confidently choose between them from the description alone.

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 no statement of when to use this tool versus alternatives such as bids.export_dataset, pipeline.export, or execution.download_artifact. The only implied guidance is that it takes an execution_id, which the schema already makes obvious. No prerequisites or exclusion conditions are given.

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