slowest_spans

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

No annotations exist, so the description carries the full burden. It does disclose the key behavioral trait — trace_id is optional and omitting it searches across all runs — which is the main thing an agent needs to know. It says nothing about ordering direction, tie-breaking, limits, or cost of an all-runs scan, which are the remaining unknowns for an unannotated tool.

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?

Three short sentences, zero filler: purpose first, then the use-case trigger, then the scoping rule. Every sentence adds information an agent would otherwise have to guess.

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?

For a simple read-only query tool with an output schema present, the description covers purpose, trigger, and scoping, so return format need not be explained. The only remaining gap is a thin treatment of k, which is minor given the parameter is optional with a default.

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 0%, so the description must compensate for both parameters. It implicitly covers k through "Top-k" and explicitly explains trace_id by describing what happens when it is omitted. It never states what k means concretely, its default of 5, or that it bounds the result size, so the compensation is partial.

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: it returns the top-k slowest spans. That is unambiguous and an agent can picture the result set. It does not, however, distinguish itself from adjacent siblings like span_tree or search_spans, so it stops short of a 5.

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?

"Use for 'why was this run slow?'" gives a concrete trigger scenario, and "Omit trace_id to search all runs" tells the agent how to widen scope. There is no explicit exclusion or named alternative (e.g. span_tree for full hierarchy, search_spans for text search), so it is clear context without routing guidance.

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