get-message

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

With no annotations, the description carries full burden. It discloses default return format (plain text) and the effect of preferHtml (returns HTML). However, it does not explicitly state it's read-only or mention any side effects, but for a get operation this is acceptable.

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 concise sentences front-loading usage, parameters, and return value. Every sentence serves a purpose, no waste.

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 tool with 2 parameters and an output schema, the description fully covers when to use, parameter semantics, and return values. No gaps for an agent to select and invoke correctly.

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?

The schema coverage is 50%, and the description adds meaning: it clarifies that id can be numeric or imap:..., and that preferHtml controls the body format. This adds value beyond the schema pattern and boolean description.

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 explicitly states the tool is for 'reading the full body of one message whose id you already have', using a specific verb and resource. It distinguishes from sibling tools like search-messages, list-messages, and get-thread.

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?

Provides clear 'Use when' and 'Do not use when' conditions, and explicitly names alternative tools (search-messages, list-messages, get-thread) for different scenarios.

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