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

Annotations already declare readOnly, idempotent and non-destructive, so the bar is lower. The description adds real behavior beyond them: a non-contract variant returns null for the filter configuration, and the returned config deliberately excludes whether unreachable types are hidden. That last caveat is exactly the kind of cross-tool trap an agent needs surfaced.

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 purpose and returned fields, then the caveats. Mostly earns its length, though 'The description states it, so read it there' is slightly redundant and could be folded into one clause.

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?

Output schema exists so return shape is covered, and annotations cover safety. The description handles the non-contract null case and the omitted unreachable-types flag. The remaining gap is thin parameter documentation on a 0%-coverage schema.

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 0%, so the description must carry the parameters. It does identify both ('Provide the graph ID and the contract variant name'), which is better than nothing, but it gives no format, naming convention, or validation detail for either. Partial compensation only.

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?

Opens with a specific verb ('Read') plus the exact resource ('the filter configuration of a contract variant') and enumerates the returned fields (included tags, excluded tags, source variant, description). It also defines what a contract variant is, which lets an agent distinguish it from siblings like GetVariantDetails and PublishContract.

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 explicit context ('the same read that `rover contract describe` performs') and routes the agent forward: read the description field before calling PublishContract, since the filter config omits the unreachable-types flag. It also states the non-contract case. It stops short of an explicit when-not-to-use-this-tool rule, but the conditions are clear.

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