Get every message in one email conversation — sender, recipients, date, subject and a snippet per message, plus whether each has attachments. Bodies are NOT included; call email_get_message_body with a message id to read one. Takes the threadKey from email_list_threads.
| Name | Required | Description | Default |
|---|---|---|---|
| threadKey | Yes | From email_list_threads. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are present, so the description carries the full burden of behavioral disclosure. It clearly states what is returned (sender, recipients, date, subject, snippet, attachment flag) and, importantly, what is NOT returned (bodies). This is sufficient for a simple read operation, though it omits minor details like error or empty-thread behavior.
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 with no filler: the main action and contents are front-loaded, the body-exclusion caveat follows, and the parameter source closes it. Every sentence earns its place.
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 single-parameter read tool with no output schema, the description fully covers what the agent needs: what comes back, what is omitted, the sibling tool to use for omitted data, and where the parameter comes from. Nothing essential 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 100% and the schema already explains threadKey as 'From email_list_threads.' The description repeats this same information in prose, adding no new semantic detail beyond what the schema provides. Baseline 3 is appropriate.
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 and resource: 'Get every message in one email conversation' and enumerates the exact contents returned. It explicitly distinguishes itself from email_get_message_body by stating bodies are not included, which makes the tool's purpose unambiguous.
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 tells the agent when not to use this tool (when bodies are needed) and names the alternative: 'call email_get_message_body with a message id to read one.' It also provides the prerequisite relationship by stating the threadKey comes from email_list_threads.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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