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

Annotations already establish read-only, idempotent, non-destructive, so the bar is lower, yet the description still discloses substantial behavior: a ten-item newest-first sample cap, the 21-day default window, that includeSeries output 'is large', and the semantics of unexplainedFailedCalls. That is real operational context beyond the structured fields.

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-loads the core purpose and then the diagnostic workflow, so the important material comes first. It is dense and packed into long comma-heavy sentences, but nearly every clause carries information an agent needs; only the sheer length keeps it from a 5.

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 full burden of describing the return shape, and it does: calls/failures vs baseline, environments with counts, sampled failedCalls fields, per-issue outcomes, and unexplainedFailedCalls. Defaults and the includeSeries switch are covered, so nothing needed to call it 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 coverage is 100%, so baseline is 3, but the description adds meaning: it explains the interaction between from and to defaults, that environment restricts counting to a single deployment environment, and that includeSeries should be left out when only numbers/samples/issues are needed. It goes beyond restating the schema without fully specifying value formats.

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?

Opens with a specific verb and resource ('Fetch one flow by id') and immediately situates it against siblings by naming the two sources of an id (list_flows, an issue's impact). An agent can tell 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 explicit routing: to read what went wrong on a route, take the fingerprint from the newest failedCalls entry and call get_issue with include=occurrences, or take the traceId to the trace tools; and states that a missing fingerprint means the trace is the only lead. It also states when to omit includeSeries. This is when-to-use, alternatives, and a conditional fallback.

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