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

With no annotations present, the description carries the full burden and does well: it discloses that nothing is executed or forked, enumerates the four possible verdict strings, and warns of a $0.01 per-span charge on the hosted surface. Missing only auth/rate-limit or failure-mode detail.

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?

A single dense sentence front-loads the action and enumeration, followed by one clause on non-execution and one on cost. No filler, and the verdict list is placed where a scanning agent will see it.

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 correctly compensates by naming the exact return values (the four FORK-* verdicts). For a nested-object forensic tool this is largely sufficient; only edge behavior on invalid or mixed spans is left unexplained.

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 coverage is 67% and the description maps the key choice (single span vs a run's span set) and reiterates the span_id scoping rule already in the schema. It adds framing but no format or validation detail for the undocumented portion of the nested span object.

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?

Uses a specific verb ("Examine ... forensically") against a specific resource (ONE recorded span or a run's span set) and enumerates the dimensions checked. It also explicitly separates itself from the sibling by stating it works WITHOUT executing or forking anything, unlike replay_span.

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 phrase "WITHOUT executing the span or forking anything" establishes when this tool applies versus an execution/replay path, and "ONE recorded span (or a run's span set)" clarifies scope. It stops short of naming replay_span as the alternative, leaving the routing inference implicit.

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