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

The readOnlyHint and destructiveHint annotations already communicate the non-destructive nature; the description reinforces this with 'without changing the schedule.' It could add more behavioral detail about what happens when conflicts are found or how conflicts are reported.

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?

The description is a single, front-loaded sentence with no filler. It packs the core action, scope, and safety qualifier efficiently.

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 read-only conflict-checking tool with a complete input schema and safe annotations, the description is largely sufficient for correct invocation. A small gap is that it does not describe what the result looks like, and the schema does not explicitly state that at least one of placement/placements must be provided.

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 parameters are already well documented. The description's 'one or up to 20' adds modest clarity around the placement vs placements parameters but does not go beyond what the schema already states.

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 uses a specific verb ('check'), a clear resource ('proposed session placements'), and an explicit scope ('one or up to 20') while also noting it does not modify the schedule. This clearly distinguishes it from scheduling tools like schedule_session.

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 'without changing the schedule' establishes clear context for using this tool as a validation/simulation step before committing changes. However, it does not explicitly name an alternative tool like schedule_session or state when not to use this tool.

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