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

Annotations already declare readOnlyHint=false, idempotentHint=false, and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful behavior language: the 402 failure when the plan's snitch limit is reached, plus the operational requirement to keep the check-in URL secret and call it each run. It stops short of noting that repeat calls create duplicate snitches.

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?

Roughly three short sentences, with the WRITE marker and resource front-loaded and no filler. The trailing endpoint notation is compact and informative rather than padding.

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?

With no output schema, the description usefully explains what is returned (the snitch and its check-in URL) and one failure mode. Auth/prerequisite and duplicate-creation behavior are unstated, leaving a small gap for a 6-parameter mutation tool.

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 83% with two enums documented in-schema, so the parameters are largely self-explanatory. The description adds no parameter-level meaning (e.g., how interval interacts with plan limits) beyond what the schema already states, which is the expected baseline.

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 ('create a new snitch (monitor)') and disambiguates it from the sibling read/update/pause tools by labeling it WRITE. The postcondition (returns the snitch with its check-in URL) further pins down what the tool produces.

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 context is implied by 'WRITE: create' among siblings and by the explanation that the returned URL must be called on every run, but there is no explicit when-to-use/when-not guidance or routing to alternatives such as deadmanssnitch_update_snitch for changing an existing snitch.

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