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

Adds real behavior beyond the annotations: inherits campaign mailboxes, tracking and stop rules; emails from the same mailbox and thread; a lead is in one subsequence at a time and enters each once; entering ends its main sequence. What is missing is the destructive/irreversible side the destructiveHint implies (whether the subsequence can be deleted, plan or count limits) and the fact that it returns the new subsequence for follow-up calls.

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, no filler, and the most consequential fact (created off, sends nothing) is front-loaded. Every clause adds operational meaning rather than restating the name.

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 deep nested create tool with 4 top-level parameters and no output schema, the description covers inheritance and the off state but not the return value (the new subsequence id, needed for update_subsequence or enroll_in_subsequence) or error conditions. Adequate, but an agent must still infer the follow-up path.

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 75%, so the schema already explains the bulk of parameter meaning, and the description adds nothing further about campaignId, name, sequence or settings. It does explain that unlisted settings are inherited from the campaign, which slightly clarifies what the caller does not need to supply.

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 ("Create a subsequence of a campaign") plus a decisive qualifier ("turned OFF"). It is clearly separable from list_subsequences, update_subsequence and enroll_in_subsequence because it makes creation, not listing, editing or enrollment, the action.

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?

"Turned OFF - it sends nothing until it is turned on in the MailBeast dashboard (or with the REST API)" gives the operating context and prerequisite an agent needs before calling. It stops short of naming sibling tools such as update_subsequence for editing an existing one, but the context is unambiguous.

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