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

Annotations already declare readOnly, non-destructive, and closed-world, so the safety profile is covered. The description adds genuinely useful behavior the annotations cannot: the enumeration of step types (model calls with tokens/cost, tool calls, lookups) and, most importantly, the 2,000-character truncation on long values. It omits any note on pagination, result size limits, or what happens with a stale/invalid traceId.

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?

Front-loaded with 'One trace' and then the content inventory; the second and third sentences add the truncation caveat and the use case without padding. The middle enumeration is long but each item earns its place by telling the agent what to expect.

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?

With no output schema, the description carries the burden of describing return contents, and it does so thoroughly (steps, timing, status, truncation threshold). It is slightly incomplete on error/edge behavior for invalid ids and on whether very large traces are paginated.

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%, including the workspace override rules and where traceId/sourceId come from, so the schema does the heavy lifting. The description contributes no additional parameter meaning, making the baseline 3 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 states a specific verb+resource ('One trace: what came in, what went out') and enumerates exactly what the retrieval returns, so an agent can immediately distinguish it from the list-style sibling. It stops short of naming caliper_traces_list as the way to discover trace ids, so sibling differentiation is implicit rather than explicit.

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?

It gives a clear use case — 'explain why one conversation went the way it did' — which tells the agent what question this tool answers. However, it offers no when-not guidance, no prerequisite chain (list first, then get), and never names an alternative tool.

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