read_an_emailOne letter whole, as the contact page's Read more opens it: who sent it, to whom and in copy, its subject, when, and the whole body as the record keeps it. Name its timeline row (an email row's id from get_contact_activity).
| Name | Required | Description | Default |
|---|---|---|---|
| activity_id | Yes | The letter's timeline row |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds only the mild behavioral note that the body is returned 'as the record keeps it', hinting at a stored snapshot, but says nothing about auth or rate limits.
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 sentences, purpose front-loaded, with the id-source constraint trailing. Slightly ornate phrasing ('One letter whole') but no wasted content.
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?
With no output schema, the description correctly carries the burden of describing what comes back (sender, recipients, cc, subject, date, body) and where the id originates. Complete for a read-only, single-param tool whose annotations already cover safety.
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 coverage is 100%, so baseline is 3, but the description goes beyond the schema's 'The letter's timeline row' by specifying the id is an email row from get_contact_activity, adding real provenance meaning for the single required parameter.
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 resource (the full email) and enumerates the returned parts: sender, to/cc recipients, subject, date, and whole body. The metaphorical 'letter' framing is clear enough, and it distinguishes the tool from read_the_mail_tommo_wont_read and the other read_* siblings by describing the complete-record retrieval.
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?
It implies the workflow by telling the agent where the id comes from ('an email row's id from get_contact_activity'), which is genuine routing guidance. However, it gives no explicit when-to-use/when-not statement or contrast against the many other read_* siblings, so usage is inferred rather than stated.
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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