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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive). The description adds genuinely useful behavior: alerts are suppressed during active windows, times are in the team timezone, and it links to external docs. It does not spell out pagination ordering beyond what the schema says, so it stops short of a 5.

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 sentences, each earning its place: scope definition, behavioral note, routing to the sibling, plus timezone and docs. Front-loaded with the core purpose; no filler.

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 values need not be explained. Given a simple read tool with full schema coverage and annotations, the description covers scope, the critical routing alternative, and a behavioral nuance (alert suppression). Nothing an agent needs to call 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 coverage is 100%, with descriptions for limit (defaults, sort order, max) and only_active_or_upcoming already in the schema. The description adds no parameter-level syntax or defaults of its own, so 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?

States a specific verb (list) and resource (one-off maintenance windows on a monitor), and crisply delimits scope as 'the ones with a fixed start and end.' It explicitly distinguishes itself from get_recurring_maintenance_periods, so an agent can pick the right tool without opening a schema.

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 the exact routing condition: scheduled/repeating windows go to get_recurring_maintenance_periods instead. It also supplies domain context on why one would care (alerts are suppressed during a window), which is real selection guidance.

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