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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds value by disclosing the shape of the response (body, direction, type, author, attachments) in the absence of an output schema, which helps the agent know what it will receive.

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?

A single front-loaded sentence plus the REST endpoint; every clause earns its place by enumerating returned fields and clarifying the Message/Note distinction. No filler.

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 reasonably compensates by listing the returned fields, and the single parameter is fully documented. Only the absence of explicit routing guidance relative to sibling read tools leaves 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 coverage is 100% for the single parameter, so the baseline applies, but the description adds provenance the schema lacks: the id comes from a ticket's message ids and identifies either a Message or a Note. That is meaningful semantic context beyond 'eDesk message id.'

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 ('Get ... message or internal note by id') and enumerates the returned content (body, direction, type, author, attachments). It clarifies the message/note duality, which is genuinely distinguishing information, though it does not explicitly contrast itself with sibling readers like edesk_get_ticket.

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 phrase 'from a ticket's message ids' implies the id must first be obtained from a ticket, which is useful implicit guidance. However, there is no explicit when-to-use statement or named alternative (e.g., edesk_get_ticket for the parent thread), so the guidance remains inferred rather than stated.

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