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

Annotations already declare readOnlyHint and destructiveHint=false, but the description goes further: it gives the exact return envelope, enumerates terminal and non-terminal statuses (queued/running/ok/error/timeout), and documents the { run: null } not-found case. That is real behavioral context an agent cannot get from 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?

Three sentences, front-loaded with the action, then the return contract, then the usage pattern. No filler and nothing repeated from the annotations or schema.

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?

There is no output schema, and the description compensates by describing the return shape and the null case in full. Combined with the polling instruction, an agent has everything needed to call this correctly and interpret the result.

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?

The schema has one parameter with 0% description coverage, so the description carries the burden. "by id from the caller's workspace" clarifies that run_id is a run identifier and that visibility is workspace-scoped, but adds no format or sourcing detail beyond that.

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 and resource ("Read the status + result of one function run") plus scope ("by id from the caller's workspace"). This clearly separates it from sibling get_function, which retrieves the function definition rather than an execution record.

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?

"Poll this after run_function until status is terminal" gives explicit sequencing and names the sibling that produces the id. There is no explicit when-not-to-use guidance (e.g. listing runs or fetching the function definition), but the triggering context is unambiguous.

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