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

Annotations only give readOnlyHint=false/destructiveHint=false, so the description carries the real behavioral load: it discloses that saves made via the link are attributed to the caller, that the link is short-lived, the required PUT header for upload, and a time-based restriction on whole-workspace write access. That is substantial context beyond the annotations.

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?

Front-loaded with the core purpose, then branching behavior, then the sibling comparison. Dense but every sentence carries operational information; slightly heavy for a four-parameter tool but not padded.

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, yet the description names the returned artifacts (file_url, container_url, sas_token) and how each is consumed, plus the attribution and expiry caveats. An agent has everything needed to call and interpret it.

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 already 100%, so the baseline is 3, but the description adds genuine meaning: it explains the path/no-path branching semantics, the readwrite-without-path failure mode, and the download vs upload HTTP methods. The api_token behavior is left to the schema.

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 specific verb+resource ('short-lived direct link to blob storage') and immediately qualifies scope: with path = one file, without path = whole workspace. It also names the sibling write_file as the alternative for small files, so an agent can tell it apart without opening either 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?

Explicitly says when to use it (large or binary files), when not to ('For files up to 3 MiB, write_file is simpler'), and how access mode interacts with path (readwrite needs a path; whole-workspace links become read-only after a stated date). Nothing is left to inference.

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