Read a thread

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

Annotations already cover the safety profile (read-only, idempotent, non-destructive), and the description adds useful thread-walking behavior and accepted input forms. However, the claim of 'everything above it and the replies below' overstates the default/maximum limits encoded in the depth and parent_height parameters, and no pagination or output-shape behavior is disclosed.

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 two concise sentences with no filler. The core behavior is front-loaded, and the use-case instruction earns its place without redundancy.

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 schema thoroughly documents all four parameters and the annotations cover the read-only safety profile, so the description does not need to re-explain those. It clearly states what the tool does and when to call it. However, with no output schema and no mention of reply-depth limits or pagination, an agent is left slightly underspecified about what will actually be returned.

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 100%, and each parameter already has a clear description, including the at:// or bsky.app URI form, depth, account selection, and parent_height. The tool description adds no parameter-specific meaning beyond what the schema already provides, so the baseline of 3 is appropriate.

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 identifies the action ('Read') and the resource ('a post together with the conversation around it'), and specifies the scope as 'everything above it and the replies below.' This distinguishes it from feed, timeline, and single-resource read tools among the siblings. The mention of accepting an at:// URI or bsky.app link further clarifies the exact target.

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 gives an explicit trigger: 'Use this before replying, so the reply lands with context.' This is a concrete and useful usage guideline. However, it does not name alternative tools or state when not to use this tool, so it stops short of a full 5.

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