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

Annotations already declare readOnly/idempotent/non-destructive, yet the description adds a genuinely non-obvious trait: 'Reading never marks anything read for you,' which an agent could not infer from structured fields. It also enumerates the fields returned per thread type, compensating for the absence of an output schema.

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 sentences, each load-bearing: what is listed, organisation scoping, and the read follow-up plus the no-read-marking caveat. The parenthetical field lists double as return-value documentation, so they earn their space rather than being filler.

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 zero-required-param list tool with no output schema, the description still covers what comes back (field-by-field), what the optional parameter changes, and what happens next. Nothing an agent needs in order to call it correctly is missing.

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 100% for the single optional parameter, so the schema already defines organisationId and its format. The description adds provenance guidance ('from traceable_workspace_projects') and states the default is the active organisation, which is modest but real added value over 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?

States a specific verb+resource: lists 'your threads', enumerating both subtypes (document Discussions and direct/group conversations) along with the identifying fields of each. It also separates itself from traceable_thread_read by positioning that tool as the follow-up rather than the listing tool.

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?

Gives a clear condition and the alternative: list here, then 'Pass an id to traceable_thread_read' to open one. It also explains the default scope (active organisation) and when to override it. It stops short of explicit exclusions, but usage is otherwise unambiguous.

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