Pattern diff (set diff across a time boundary)

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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, openWorldHint), so the bar is lower, and the description still adds real behavioral context: how re_emerged is derived (checking first_seen against the before-window boundary), how co-emergence clusters fingerprint a deploy with default 60s window, and that an incidents block is emitted when clusters are found. It stops short of noting limits, auth, or large-window cost behavior.

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?

The core definition and the labeled sets are front-loaded and the Scoping/Returns structure helps. But roughly a third of the text is competitive marketing ('coherent ONLY because log10x pattern_hash is stable... competitors that re-cluster per query') that does not help an agent select or invoke the tool, so several sentences do not earn their place.

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 9-parameter tool with an output schema and read-only annotations, the description is complete: it explains usage triggers, scoping, defaults, the semantics of each returned set, and the conditions under which an incidents block appears. Nothing an agent needs 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 description coverage is 100%, so the schema already documents all nine parameters, and the description largely restates them (timeRange window pairing, limit rows-per-category, service/severity scoping). The re_emerged boundary semantics and cluster-fingerprint framing add a little meaning beyond the schema, but not enough to rise above the baseline for full coverage.

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+scope ('Set diff of patterns across a time boundary') and enumerates exactly what is computed: the new/retired/persistent/re_emerged sets plus co_emergence_clusters. This is unambiguous and clearly distinguishable from look-alike siblings such as log10x_pattern_trend or log10x_whats_changing, which do not produce a set diff.

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?

Concrete trigger phrases are given ('what changed since last deploy', 'which patterns disappeared this week', 'did the rollback bring back the old errors') and it names a specific companion call (log10x_pattern_examples on a flagged hash). However it never explicitly distinguishes itself from the similarly-purposed siblings log10x_whats_changing and log10x_pattern_trend, leaving that disambiguation to inference.

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