get_message

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

With no annotations the description carries the full load, and it discloses non-obvious traits: body is converted to plaintext, truncated, and the truncation exists for token economy. It does not cover invalid/expired ref behavior or whether attachments/HTML structure are dropped, which are the remaining gaps for a read tool.

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-loaded sentence states purpose and the two most important behaviors (plaintext, truncation) before the Args breakdown. The Args block is tight, though it slightly duplicates the schema's field names.

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?

No output schema exists, and the description covers what comes back: subject/from/date in metadata-only mode and a plaintext body otherwise, plus the size cap. Error handling and ref lifetime are the only notable omissions for a single-item read tool.

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 0%, so the description must compensate, and it does: it explains the accepted id formats, the effect of include_body, and the semantics of max_chars including the 0 sentinel. It omits the actual default values (4000 and true) that the schema declares, so an agent must open the schema for those.

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 one message by ref') and pins the identifier form ('a short ref from list_messages, or a raw Graph id'). It is clearly differentiable from list_messages, which is named as the source of refs.

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?

Gives actionable per-parameter usage: include_body=False for metadata-only, max_chars=0 for no limit. The ref-from-list_messages hint establishes the workflow. It stops short of explicit when-not-to-use guidance (e.g., use list_messages for searching, or bulk tools for many messages).

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