post_service_lines_by_service_line_number_user_terminals

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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the tool's non-destructive write nature is known. The description adds required permission and prerequisite, but does not disclose idempotency, side effects, or behavior if the terminal is already associated with the service line. This adds moderate value beyond 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 single sentence plus a prerequisite and endpoint reference. It is front-loaded with the action, contains no redundant words, and each part earns its place.

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 mutable tool with 2 parameters and no output schema, the description covers the action, prerequisite, and permission. It is missing potentially useful details like idempotency or error conditions, but is largely complete for its complexity level.

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?

Input schema covers both parameters with descriptions, so baseline is 3. The description adds context that deviceId must reference an existing account terminal, which is not in the schema. This helps the agent understand parameter constraints better.

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 'Add user terminal to service line' with a specific verb and resource. It distinguishes from sibling tools like post_user_terminals (adds to account) and delete_service_line_user_terminal (removes), making the tool's purpose unambiguous.

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?

Provides explicit prerequisite: user terminal must already be on the account, and references the endpoint to add it (POST /v2/user-terminals). It also specifies required permission. However, it does not explicitly contrast with other sibling tools like delete_service_line_user_terminal, so some context is implicit.

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