zoho_send_email

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

Annotations already disclose readOnly=false, destructive=false, openWorld=true, but the description adds the crucial point that this 'sends real mail immediately' and should be confirmed with the user — an irreversibility/side-effect warning not captured by the hints. It doesn't describe failure modes or rate limits, but the human-in-the-loop warning is high-value context beyond the annotations.

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 sentences, zero filler: core purpose first, the safety warning second, the cross-tool prerequisite last. Each sentence earns its place and the most important (irreversible send) point is front-loaded.

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 14-parameter, no-output-schema tool, the description covers the highest-risk aspects (real send, user confirmation, attachment prerequisite) while scheduling and format details live in the schema. Nothing critical is missing, though failure/auth behavior is unaddressed.

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 79% (near the baseline-3 threshold), and the description adds meaning beyond the schema by tying the attachments parameter to the zoho_upload_attachment prerequisite and noting the returned objects must be passed through. It also implicitly links 'scheduled' to isSchedule/scheduleType, complementing the already-well-documented params.

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 ('Send an email') and covers optional modifiers (attachments, scheduled) that map to the schema. It's clearly distinguishable from closely related siblings like zoho_save_draft and zoho_reply_to_email, though it never names those alternatives explicitly.

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 real operational guidance: confirm recipients/content with the user first, and call zoho_upload_attachment before this tool when attachments are needed. It stops short of naming sibling alternatives (e.g., save_draft vs send) or stating when-not-to-use, so it's clear context without explicit exclusions.

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