New errors

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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety is covered. The description adds real behavioral context beyond that: the dedup rule that messages differing only by IDs count as one error, that each entry carries counts, first-seen time and a redacted example line, and that steady services are also reported. Auth, rate limits and ordering are not disclosed.

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, but front-loaded with the core comparison and then the result contents in priority order; every clause (dedup rule, counts, first-seen, redaction, steady services) carries information. It reads as a run-on, which costs a point, but nothing is padding.

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?

There is no output schema, so the description must carry the return contract — and it does, enumerating the three result groups and the per-entry fields. What is missing is edge behavior: what happens when budget_tokens truncates results, ordering, and the exact shape of 'steady' services versus the rising ones.

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% and all five parameters (since, until, service, baseline, budget_tokens) are fully documented in the schema with defaults and formats. The description reinforces the baseline-comparison concept but adds no syntax, units or format detail beyond what the schema already states, so the baseline of 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?

The description names the specific analysis performed (error logs compared against a baseline) and the three result categories: new/spiking errors, services with error volume rising beyond traffic, and steady-error services. It is clearly distinguishable from list_services and trace_diff, though it never names a sibling explicitly.

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?

Usage is implied by the output framing — an agent can infer this is the tool for spotting newly introduced or regressing errors versus a baseline. However, there is no explicit when-to-use guidance, no statement of when NOT to use it, and no routing against the sibling what_changed, which could plausibly overlap.

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