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

Annotations already declare readOnly/idempotent/non-destructive, so the description is free to add the behavior that matters: what the call yields ('Shows each section's ID and the slots you can fill'), which is key since there is no output schema. It adds no notes on result volume or whether sections are user-defined vs built-in, but the value-add is real.

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 short sentences, front-loaded with what the tool is, followed by what it returns, followed by the alternative. Nothing is restated or padded.

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 two-optional-filter listing tool with no output schema, the description covers what is returned (IDs plus fillable slots) and where to go for content outside its scope. An agent can select and call it correctly with nothing further.

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 both filters are already documented. The description's category examples (headers, banners, products, footers) loosely echo the schema's category examples but add no syntax, matching behavior, or default semantics beyond it. Baseline 3 is correct.

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 (browse) and a precisely scoped resource (the drag-and-drop editor's ready-made sections, enumerated as headers/banners/products/footers). It also distinguishes itself from two neighbors: the consumption point (create_dnd_email_template) and the broader catalog resource (mailercloud://email-blocks/catalog).

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?

Explicitly frames the use case ('to use in create_dnd_email_template') and routes the agent to the alternative for other content types ('The full catalog (settings, layouts, blocks) is the resource mailercloud://email-blocks/catalog'). No explicit 'when not to use' beyond that routing, which keeps it short of a 5.

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