cb_log

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is fully covered. The description adds the '只读' (read-only) label, which is consistent with annotations. It doesn't add behavioral context beyond that, such as what events are included, ordering, or whether the timeline is filtered by branch. With annotations covering the safety profile, a 3 is appropriate – the description adds minimal behavioral context beyond the annotations.

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 states the core purpose and read-only nature. It's front-loaded with the key information. It could arguably add a bit more context about what the timeline contains, but for a simple read-only tool, the brevity is appropriate.

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?

Given the tool's simplicity (2 params, 1 required, no nested objects, output schema present), the description is mostly complete. The annotations cover the safety profile, and the schema covers parameters. The only gap is that the description doesn't explain what kind of events appear in the timeline or how the output is structured, but the output schema likely covers that. For a read-only timeline viewer, this is adequate.

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%, so both parameters (root and limit) are already documented in the schema. The description doesn't add parameter-level detail beyond what the schema provides. The 'limit' parameter's meaning ('只看最近 N 条事件') is already in the schema, and 'root' is described as the workspace root. Baseline 3 is correct when the schema does the heavy lifting.

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 '查看工作区事件时间线（只读）' clearly states the tool's purpose: viewing the workspace event timeline, and explicitly marks it as read-only. It distinguishes itself from sibling tools like cb_diff, cb_status, and cb_checkout by focusing on the event timeline rather than file diffs, status, or branch operations. However, it doesn't explicitly name a sibling alternative, so it doesn't fully differentiate itself from all 14 siblings.

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 implies usage context: it's a read-only timeline viewer for the workspace, and the '只读' (read-only) marker suggests it's safe to use for inspection. However, it doesn't explicitly state when to use this tool versus alternatives like cb_status or cb_log. The annotation readOnlyHint=true reinforces the safe-inspection context, but the description itself provides no explicit when/when-not guidance.

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