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

Annotations already declare this is a non-read-only, non-destructive mutation, so the safety profile is covered. The description adds useful actor context ('kernels'), but does not disclose state-transition rules, permissions, side effects, or return behavior beyond that.

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 short sentences, front-loaded with the operation and scope, with no filler. Every sentence earns its place.

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?

For a simple three-parameter mutation with full schema coverage and annotations covering safety, the description gives enough purpose and usage context to invoke it correctly. Minor gaps remain around state transitions and permissions, but they are not critical for this 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%, so the schema already fully documents jobId, status values (including the legacy alias), and progress range. The description only repeats status and progress without adding format or constraint details beyond the schema, matching the baseline 3.

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 states a specific verb and resource ('Update a job's status and optional progress percentage') and adds who uses it ('Used by kernels'), which helps separate it from operator-facing siblings. However, it does not explicitly name or contrast with the close sibling operator_update_job_status, so it stops short of full differentiation.

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 phrase 'Used by kernels to report job progress' gives a clear context for when this tool is appropriate. It does not include exclusions or named alternatives, but that is consistent with a 4 under the rubric.

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