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

Annotations already declare readOnly=false, destructive=false, and idempotent=false, so the write semantics are partially covered. The description adds genuinely useful partial-update behavior ('supply only fields to change'), but leaves the critical ambiguity unresolved: whether omitted nested objects/arrays (options, destinations) are preserved, merged, or replaced, and whether changes are reversible.

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 compact sentence, front-loaded with the verb/resource and followed by the one operational instruction that matters. Nothing is padded, but the brevity crosses into under-specification rather than deliberate economy.

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 16-parameter mutation over deeply nested structures with no output schema and no field-level docs, an agent cannot determine merge-vs-replace behavior, valid schedule/timezone formats, or what a successful update returns. The description is well short of what this schema's complexity demands.

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 0% across 16 parameters, including a nested options object with roughly 30 fields and polymorphic destinations/outputs. The description only says which parameters to include, not what any of them mean, so it does not compensate for the documentation gap.

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 and resource: 'Update a screenshot schedule'. That is clear against create_schedule/delete_schedule, though it does not explicitly differentiate from pause_schedule, resume_schedule, or trigger_schedule, which are the siblings most likely to be confused with a modification tool.

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?

'Supply only fields to change' implies the PATCH-style usage context and is the only routing signal given. There is no statement of prerequisites (does it need an existing schedule id?), no exclusions, and no pointer to pause_schedule/resume_schedule for state changes.

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