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

Annotations already cover safety (readOnly, idempotent, non-destructive), so the bar is lower. The description adds genuinely new context: it is free, finishes in a few seconds, does not create a timetable, and returns VALID (with warnings) or INVALID (with reasons) — a meaningful disclosure given there is no output schema.

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?

Three short sentences, front-loaded with the primary action and scope, then mechanics, then the routing instruction. No redundant restatement of the name or title.

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 validator with a rich nested schema, the description supplies what structured data does not: runtime expectation, cost, that no timetable is produced, and the two possible outcome states. Nothing needed to invoke it correctly is missing.

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%, including the nested 'files' object with all 8 named keys and format notes, so the schema carries the parameter burden. The description only references 'the 8 input files' and adds no syntax or format detail beyond the schema — 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?

Specific verb+resource: checks the 8 input files and enumerates what is checked (file structure, engine limits, capacity analysis). It explicitly distinguishes itself from create_schedule by stating it does so 'without creating a timetable', so an agent can route between the two without opening schemas.

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 an explicit directive and ordering: 'Always run this before create_schedule', naming the sibling it precedes. The condition that selects this tool (pre-scheduling validation) is unambiguous.

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