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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the safety profile is partly covered. The description adds nothing beyond that: it does not say whether creation is idempotent, what happens on duplicate interfaces, whether the new contract is locked by default, or what identifiers come back. For a create tool with nested objects and an explicit 'lock' flag, meaningful behavioral context is missing.

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?

A single front-loaded sentence with zero filler, so nothing needs trimming. Its brevity is efficient rather than padded, though it is arguably too thin to earn a top score on structure.

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?

The output schema exists, so return values need not be explained, and the 100%-covered input schema documents fields. Still, for a creation tool over two subsystem references with nested metadata, the description omits any notion of required prior state, duplicate handling, or how the interface is scoped to the project, leaving a noticeable gap.

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 rich nested schema (source/target subsystem ids, interface_type enum values DATA/TRIGGER/STATE, description_payload, lock, content metadata) already carries full parameter meaning. The description adds no format, constraint, or payload-shape guidance beyond it, so the baseline 3 applies.

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 gives a specific verb+resource ('Create an interface contract') and adds scope ('between two subsystems'), which is enough to distinguish it from interface_contracts_update, interface_contracts_patch, and interface_contracts_get just by name. It does not, however, explicitly contrast itself with any sibling, so it lands at 4 rather than 5.

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?

There is no guidance on when to use this tool versus interface_contracts_update or interface_contracts_patch, and no prerequisites are stated (e.g. that project_id and both subsystem UUIDs must already exist). The agent must infer usage entirely from the verb.

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