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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so safety is covered. The description adds genuine value by disclosing the shape of the payload (status, outcome, expiry, resource addresses/URLs), which helps an agent know what it will receive.

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?

Two tight sentences, front-loaded with what the tool returns before the usage hint. Every clause carries information, though the phrasing 'with the address or URL each answers at' is slightly dense.

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?

With no output schema, the description carries the return-value burden and does so by naming the key fields plus the resource addresses. For a single-parameter read tool with full annotation coverage, this is essentially complete, only lacking pagination/edge-case notes.

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 100% and run_id is fully documented in the schema ('A run id from rig.run.create'), so the schema does the heavy lifting. The description adds no additional parameter meaning, making the baseline 3 appropriate.

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 ('get' one run) and enumerates what a run carries: status, outcome, expiry, and resources with their addresses/URLs. This is clear, though it never explicitly distinguishes itself from siblings like rig.run.create or rig.run.cancel.

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?

Gives a concrete use case ('Read this for the addresses to configure in the application under test'), which tells the agent when this tool is the right pick. No explicit alternatives or exclusions are named, but the context is clear.

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