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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered by structured data. The description adds a useful constraint (automations can only send resources present in this list) but says nothing about pagination, ordering, or how many items come back.

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 tight sentences with no filler, front-loaded with the entity definition that an agent needs first. The second sentence is slightly elliptical ('one that exists here') but earns its place by adding a real precondition.

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 read-only, single-optional-parameter list tool with no output schema, the description supplies the conceptual shape of the returned items, which is what an agent needs to interpret results. Return format and pagination are unaddressed, but the simplicity of the tool makes that a minor gap.

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 100% for the single workspaceId parameter, including its default behavior, so the schema does the work. The description only alludes to workspace scoping via 'of this workspace' and adds no format or override detail 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?

The description defines the resource precisely — 'the guide, template, file or link a DM sends when someone asks for it or comments a keyword' — which makes the listed entity concrete and distinguishes it conceptually from create/update/delete siblings. It never states the listing verb itself (that comes from the name and title), so it stops short of a fully self-contained purpose statement.

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?

'An automation can only send one that exists here' implies the use case (verify availability before wiring an automation) but is phrased as a domain constraint rather than guidance. No explicit when-to-use, when-not-to-use, or alternative sibling (create_dm_resource, update_dm_resource) is named.

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