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

Annotations already declare readOnlyHint=true, openWorldHint=false, destructiveHint=false. The description reinforces this ('Only READS — returns a proposed assignment per job') and uniquely discloses that the output is a preview (not persisted) and what happens to unplaceable jobs. This is genuine added context beyond the annotations.

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 well-structured sentences: first states purpose and constraints, second clarifies behavior and next step. Zero wasted words.

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?

Given no output schema, the description helpfully explains the return shape (proposed assignment per job, plus unplaced jobs) and the apply path. It's complete enough for an agent to call correctly, though it could say more about the balancing algorithm's edge cases.

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 100%, so defaults and ranges (default +6 days, at most 21 days, 5-600 minutes) are already fully documented in the schema. The description adds no parameter-level detail beyond what the schema provides.

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+scope: 'Plan who does which open, unassigned job over a date range, balancing booked minutes under a daily cap.' Clearly distinguishes from siblings like plan_day_routes and tech_workload by being an assignment-planning operation over unassigned jobs.

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?

Explicitly names the follow-up step and tool: 'To make it real, pass the assignments to apply_schedule.' Also clarifies this is a read-only preview that produces proposed assignments, and what happens to jobs that couldn't be placed.

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