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

The description adds significant behavioral context beyond the annotations: it explains that emailBodyText is converted by MCP to content.root, that business permissions must be checked, and that FREE businesses are prohibited regardless of feature rows. It also requires surfacing grace-period warnings and a resubscribe link before proceeding. This is rich behavioral disclosure not present in the readOnly/destructive hints. No contradiction with 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?

The description is a compact paragraph of four sentences, each adding value: purpose, content modes, access prerequisite, and mandatory warning behavior. No filler or redundancy; it is well-structured and easy to parse.

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?

The description covers the essential operation and important preconditions (business access, FREE restriction, content conversion), but for a tool with 20 parameters and no output schema, it omits details about update semantics (partial vs full update), return values, or how optional parameters interact. The high-level context is adequate, but the complexity of the tool suggests more detail is needed for complete agent guidance.

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 only 20%, and the description only elaborates on two parameters (emailLexicalContent and emailBodyText) by explaining the conversion to content.root. The remaining 15+ parameters (title, author, isDemo, selectedUsers, sentPlatforms, etc.) are left unexplained. Given the low coverage, the description does not sufficiently compensate for the schema gaps, making parameter semantics incomplete for correct invocation.

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 clearly states the action: 'Update a Magic Reach message for a managed community.' The verb 'update' plus the specific resource ('Magic Reach message') makes the purpose unambiguous. It also distinguishes from sibling tools like create_magic_reach_message or send_magic_reach_message by focusing on the update semantics.

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 gives strong usage guidance: it explicitly instructs to call check_business_tool_access before collecting inputs and states that FREE businesses cannot use this tool. It also says to show any grace-period warning and verified resubscribe link before continuing. It does not explicitly name alternative tools, but the context of 'update' versus 'create' or 'send' is clear enough.

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