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

Annotations only declare readOnlyHint=true; the description goes well beyond, explaining that 404 is returned for an unknown id rather than an empty template, that the summary/full split is deliberate for token cost, and what the read is used for. This is genuine behavioral context the annotations cannot supply.

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-loads the core purpose, then the sibling differentiation and the anti-pattern, then the 404 behavior. Slightly long but every sentence earns its place; only minor tightening possible.

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?

Output schema exists so return values need not be restated, yet the description still names the returned fields, explains the summary-vs-full tradeoff, warns about ids, and covers error behavior. Nothing an agent needs in order to call correctly is missing.

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% and the single parameter's format ('tmpl-…' id) is fully documented in the schema. The description reiterates the id source but adds no syntax beyond what the schema provides, so the baseline 3 is appropriate.

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 ('Read ONE template in full') and enumerates exactly what is returned — subject, HTML body, fromEmail, type, version, variables. It explicitly distinguishes itself from volanea_list_resources and volanea_create_template, which return bodyless summaries.

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?

Provides explicit when-to-use ('inspect or restyle existing content', 'check which placeholders a send must supply') and an explicit when-not-to-use ('Do NOT use it to discover ids — volanea_list_resources { templates } is far cheaper'). This is textbook routing guidance.

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