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

With no annotations, the description does useful work by disclosing the auth requirement ('Requires a Bearer API key') and the folder-scoping of identifiers. However, it omits that reading can mutate state via markAsRead (default true for full account keys) and says nothing about the 409 conflict path or error behavior, leaving a read-with-side-effects tool under-described.

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?

Two short sentences, front-loaded with the action and resource, then the auth constraint. Nothing is padded or redundant.

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 four-parameter read tool with no annotations and no output schema, the definition covers the essentials (what it reads, how it is addressed, auth) but leaves the read-state side effect and conflict behavior unaddressed. Adequate to invoke correctly in the happy path, thin for edge cases.

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?

At 50% schema description coverage, the description compensates partially: 'folder-scoped UID' adds the important meaning that id is only unique within a folder, which the schema itself does not state. The markAsRead and uidValidity semantics are left entirely to their schema descriptions, and the folder parameter gets no mention in the 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?

States a specific verb and resource ('Read a message') plus the addressing scheme ('folder-scoped UID'), which is more precise than the name alone. It does not explicitly contrast with the sibling check_inbox, which also surfaces messages, so the agent must infer that get_email is for fetching one already-known message.

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?

There is no explicit when-to-use or when-not-to-use guidance, and no mention of the sibling check_inbox as the alternative for listing. The 'folder-scoped UID' phrasing only implies that the caller must already have a UID, presumably from a list or webhook, without saying so.

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