list_threads

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

The readOnlyHint already declares this is a safe read. The description goes beyond that by disclosing result ordering (newest first), that each thread carries its latest message, and the per-line output shape beginning with the thread id. It does not mention pagination or result caps, but with an output schema present the return shape is already partly covered.

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 short lines, zero filler, and front-loaded with the core purpose and ordering before the read_thread linkage and the single parameter note. Every sentence 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?

With an output schema present the description need not explain return values, and it covers ordering, per-line format, and the read_thread connection. The main gap is the undocumented limit and unread_only parameters, which is a minor omission for an otherwise simple read-only listing tool.

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 0%, so the description carries the burden, yet it only documents one of three parameters: 'contact: optional name or number fragment to filter on.', which usefully clarifies the fragment-matching semantics. limit and unread_only are left entirely to their self-explanatory names and defaults, so compensation is partial.

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 ('List SMS conversations') and adds distinguishing scope: newest-first ordering and inclusion of the latest message per thread. It also names the sibling read_thread and explains the linkage (thread id), so an agent can separate this listing tool from the read-one tool without opening either schema.

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?

Usage is implied through the read_thread linkage ('Each line starts with the thread id, which read_thread takes'), which does suggest a list-then-read workflow. However, there is no explicit when-to-use vs when-not, no mention of find_contact or send_sms, and no stated prerequisites.

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