update_sms_thread

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

With no annotations, the description carries the full burden. It details key behaviors: tags can be appended or replaced via `append_tags`, notes have a max length and reject empty strings, and account_id auto-resolves. It does not mention error cases or authorization requirements, but provides substantial transparency.

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 concise: a single-sentence purpose followed by a note about the gap, then a clear list of arguments. Every sentence adds value with no redundancy. It is front-loaded with the core purpose.

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 all 7 parameters with detailed semantics and provides usage context. An output schema exists, so return values are covered elsewhere. It does not mention error scenarios or prerequisites, but for an update operation this is sufficient.

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 0%, so the description must compensate entirely. It does so excellently by explaining each parameter: thread_id source, notes constraints, value numeric, tags behavior with append_tags, lead_qualification configurability, and account_id auto-resolution. This adds significant meaning beyond the schema.

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 it updates an SMS thread's lead-management fields, identifies specific fields (notes, value, tags, lead_qualification), and distinguishes itself as the texting equivalent of `update_call`. This provides a specific verb+resource and differentiates from sibling tools.

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 explains when to use the tool (to tag, note, or qualify texting leads via API) and references `update_call` as an analogue. It lacks explicit when-not to use or alternatives, but the context is clear enough to guide selection.

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