subscriptions_thread_mark

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

The description includes a useful note that this is an 'undocumented session endpoint,' hinting at potential instability or lack of official support. However, it does not disclose error behavior, idempotency, permission requirements, or side effects beyond marking state. With no annotations available, more detail would be beneficial.

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, concise sentence that front-loads the core action. It avoids unnecessary words but could include a brief statement about intended use cases or limitations without sacrificing conciseness.

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 state-marking tool with a known output schema, the description covers the primary behavior. However, it lacks information on how the tool handles edge cases (e.g., thread already marked, invalid IDs) or what response to expect. The 'undocumented session endpoint' note adds important context but does not fully compensate for missing behavioral details.

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 provides full descriptions for all three parameters, achieving 100% coverage. The tool description adds minimal semantic value beyond restating the action; it does not clarify usage context for parameters like channel or thread_ts, which are already well-described in 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?

Description clearly states the action ('Mark a thread as read or unread') and the target resource (a thread), making it distinct from sibling tools like conversations_mark which operate on channels. The verb-resource combination is specific and 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?

No guidance is provided on when to use this tool versus alternatives such as conversations_mark or chat_update. There is no mention of prerequisites, success conditions, or when it should be avoided. Users must infer context from the tool name alone.

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