Mark emails as unread using message IDs or entire conversations using thread IDs. Restore unread status for individual messages or threads in Zoho Mail.
Mark emails as unread. Target individual emails with messageId, or whole conversations with threadId (give one of the two).
| Name | Required | Description | Default |
|---|---|---|---|
| threadId | No | ||
| messageId | No |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare this is a mutation (readOnlyHint=false) that is not destructive (destructiveHint=false) in an open world. The description adds the targeting semantics (one ID type per call) but discloses nothing about permissions, batching, idempotency, or side effects of unread-marking. Against existing annotations, this is adequate but not rich.
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, zero waste, front-loaded with the action and followed by the parameter-routing rule. Every clause earns its place; nothing is redundant with the structured fields.
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 two-parameter mutation with annotations covering its safety profile and no output schema, the description is largely sufficient: the agent knows the action and how to target it. It omits confirmation behavior and any permission prerequisites, but nothing critical for correct invocation 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?
Top-level schema description coverage is 0%, so the description must compensate and it does add real meaning: messageId addresses individual emails while threadId addresses whole conversations, and exactly one must be supplied. It does not explain the array/minItems shape or the string-precision note, so it is not fully complete.
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: 'Mark emails as unread.' It also clarifies scope by explaining that the target can be individual emails (messageId) or whole conversations (threadId). It does not explicitly distinguish itself from the close sibling zoho_mark_threads_unread, leaving potential ambiguity about which thread-marking tool to use.
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?
Gives clear parameter-selection guidance: use messageId for individual emails, threadId for whole conversations, and 'give one of the two'. This tells the agent how to invoke it correctly. It stops short of naming an alternative tool or stating exclusions/conditions that would route away from this tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.