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

Annotations already declare readOnlyHint=false, idempotentHint=false, and destructiveHint=false. The description adds meaningful behavior beyond that: a new version is published at the SAME URL, the server does the substitution (no HTML sent), and the call fails if any placeholder lacks a value. That failure condition and the URL-stability guarantee are useful context the annotations don't convey.

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?

Front-loaded with the core action and kept to a handful of sentences. Slight redundancy: the 'every placeholder must have a value or the call fails' rule is already stated in the schema description, so one sentence partially repeats structured data.

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 does usefully explain the effect (a new version at the SAME URL) rather than a return payload. Combined with the template precondition, failure mode, and data format, an agent has what it needs to invoke it correctly, though the response shape is only implied.

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%, so the baseline is 3. The description nevertheless adds value: a concrete example of the `data` map ({"leads": "3 200", "date": "..."}), the rule that every placeholder must be present, and the explicit note that values are substituted server-side so no HTML is passed. This clarifies the semantics of `data` beyond the schema's field list.

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 pair ('Re-render a data-driven artifact') plus the key mechanism (template + data payload, published to the SAME URL). This is highly specific. It does not explicitly name a sibling (e.g. artifacts_update) to contrast against, so it falls just short of the 5 bar for differentiation.

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 a clear when-to-use signal ('Ideal for scheduled refreshes of live numbers') and a precondition (artifact must have been created/updated with a template). It does not state when NOT to use it or name an alternative tool, so no exclusion guidance.

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