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

Annotations already declare readOnlyHint=true, and the description adds behavioral detail beyond that: the 100-item cap, tags on each monitor, and a total count to detect truncation. These are operationally useful traits not present in the annotation or schema. No contradictions with 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 compact sentences, with the core action front-loaded before the filter and return-value notes. No filler or unrelated content, and every sentence earns its place. The description is appropriately sized for the tool's simplicity.

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 tool with no output schema, the description covers the essential return semantics: a list of monitors with tags and a total count for truncation detection. It does not specify the exact monitor fields (e.g., ID) or ordering, but those are predictable for a list-monitors tool. Given the simple one-optional-param signature and read-only annotation, the description is nearly complete.

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?

The single parameter (tag) is fully described in the input schema, including optionality and case-insensitive matching. The description's 'Can be narrowed to one tag by name' is largely redundant with the schema. With 100% schema coverage, the baseline 3 applies; the description adds no meaningful parameter information beyond the schema.

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 ('Fetch'), a specific resource ('the authenticated user's website monitors'), and explicit scope ('up to 100, each with the tags it carries'). Also mentions the optional tag filter and the return of total count, so there is no ambiguity about what the tool does. It clearly distinguishes itself from monitoring-query siblings by focusing on the list itself.

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?

The description gives clear context: use this to retrieve the user's monitors, optionally filtered by one tag. It does not explicitly name alternatives or give 'when not to use' guidance, though the sibling set makes the distinction (e.g., get-monitor-incidents for incidents, get-uptime-stats for metrics). Clear context but no exclusions.

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