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

Annotations already declare readOnlyHint and openWorldHint=false, so safety is settled. The description adds real behavioral context beyond that: newest-first ordering, 50-per-page batching, truncated Q/A text, and the fields returned (tools, time, tokens, cost, status). It doesn't state a total count or rate limits, keeping it just short of a 5.

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?

Two sentences, front-loaded with what is listed and how it is ordered, followed by filtering, paging, and the sibling handoff. Dense but every clause carries information; only the return-field enumeration is slightly list-like.

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?

No output schema exists, so the description compensates by naming the returned fields and pagination contract, and it covers the filter and paging parameters. Nothing needed to call or interpret this tool 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 description coverage is 100%, so the schema already documents all 7 parameters, including the workspace/token caveat and the YYYY-MM-DD pattern. The description echoes the filter set (day, tool, document, failures) without adding syntax beyond the schema, so the baseline 3 applies.

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 ('traces behind a point on a source's chart') plus ordering and page size, which distinguishes it from caliper_traces_get, the single-trace sibling. An agent knows exactly what this returns without opening the 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?

Gives concrete narrowing dimensions (day, tool, document, failures), the paging protocol (`before` = nextBefore from last page), and explicitly routes to caliper_traces_get for a single trace. Both when-to-use and the alternative are covered.

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