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

Annotations only supply destructiveHint=true; the description adds genuine behavioral context beyond that by disclosing the PUT/upsert model and the partial-update contract ('sends only the fields you provide'). It stops short of warning that list-valued fields like tags/notify/assertions are replaced wholesale, which is relevant given the destructive hint.

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 tight sentences with no padding: the upsert behavior is front-loaded, followed by a concrete usage example and the API/partial-update contract. Every clause carries information the agent can act on.

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 10-parameter, nested-object mutation tool with a single required key, the description covers the essential upsert and partial-update semantics (no output schema means return values need not be explained). The remaining gap is the absence of any mention of how array fields are handled on update.

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 the schema already documents all 10 parameters including examples for schedule and paused. The description repeats the paused:true and schedule examples but adds no syntax or format detail beyond what the schema provides, 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+resource (create/update a monitor by key) and captures the upsert nature via PUT semantics, which is meaningful because the key is required. It does not, however, differentiate itself from the sibling cronitor_create_monitor, leaving the agent to infer whether create should route here or there.

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?

Usage is implied through examples ('change schedule', 'pause via paused:true') but there is no explicit when-to-use or when-not guidance relative to cronitor_create_monitor or cronitor_get_monitor. The agent must infer the upsert-vs-create distinction on its own.

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