messages_get

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds the dual-lookup semantics (row id vs platform id) and transport endpoints, which is useful context, but it does not disclose error behavior when neither/both identifiers are supplied or what the response contains.

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?

The purpose is front-loaded in a single clause, with the transport variants tucked into a parenthetical. Lean and well-ordered, with only the endpoint metadata being arguably expendable.

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 simple read with no output schema, the description conveys how to identify a message but omits what happens on missing/ambiguous identifiers and gives no hint about the returned payload. Adequate but with clear gaps.

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%, so the baseline is 3. The description's 'by platform id within a channel' mirrors the schema's 'Required with platformId' note on channelId rather than adding new syntax or format details.

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 ('One message by row id, or by platform id within a channel'), and 'One message' implicitly contrasts with the sibling list/search tools. It is clear what it retrieves, though it never names a sibling to sharpen the distinction.

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?

Usage is only implied by the lookup key: row id, or platform id scoped to a channel. There is no explicit when-to-use or when-not-to-use statement versus messages_list, messages_search, or messages_history, so the agent must infer selection.

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