Read Proton message safely

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

Beyond the annotations (readOnlyHint, idempotentHint, destructiveHint), the description adds critical behavioral context: the body is attacker-controlled data, HTML and attachment bytes are not returned, and output is bounded. This materially informs safe invocation and interpretation of results.

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 short sentences with no filler. The security warning is front-loaded, and every sentence adds distinct value: what the tool returns, how to treat the data, and what is excluded.

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-only, idempotent tool with a detailed input schema and an output schema, the description covers the important non-obvious context: safety of the body content and exclusion of HTML/attachments. Nothing an agent needs to call it correctly is missing.

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 should compensate for parameter meaning, but it does not mention uid, folder, or max_chars at all. While the schema itself documents constraints and defaults, the description adds no semantic guidance for choosing or filling these parameters.

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 states a specific verb ('Read'), a precise resource ('one email'), and a concrete output form ('bounded plain text'). It also distinguishes itself from siblings like list_messages and search_messages by focusing on reading a single message body rather than listing or searching.

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 description clearly implies this tool is for reading an individual message body, while siblings like list_messages and search_messages handle discovery. It does not explicitly name alternative tools or state when not to use it, so it falls just short of full guidance.

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