vexo_event_timeline

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

Annotations already declare readOnlyHint=true and openWorldHint=true. The description adds valuable behavioral details: UTC bucketing, auto-split for ranges over 31 days, meaning of gaps (no events), and error response format. These go beyond annotations and clarify important aspects not visible in the schema.

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 description is well-structured with a clear purpose sentence, followed by use case, parameter list, and return output. It is concise but thorough, with each sentence adding value. A minor redundancy exists (event_names requirement stated twice) but does not detract.

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?

Despite having no output schema, the description provides a detailed return structure including fields like window, granularity, group_by, rows, truncated, and total_count. It explains sorting and gap semantics. Missing precision on optional total_count and truncation behavior, but overall complete for a tool of moderate complexity.

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?

With only 14% schema description coverage, the description compensates by explaining each parameter's semantics: event_names as required list with example, start/end_date as ISO dates (end inclusive), group_by defaulting to server key, filter_values with max 200, and granularity limited to 'day'. This adds significant meaning beyond the bare schema.

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 clearly states it provides a per-day timeline of specific events for detecting cutover dates. It distinguishes itself from siblings like vexo_count_events (which counts events without bucketing) and vexo_get_recent_events (which returns raw events) by emphasizing the day-level aggregation and cutover detection use case.

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 description explicitly recommends using this tool for cutover detection and notes that event_names is required. While it does not mention alternatives or when not to use it, the specificity of the use case and required parameters provide strong guidance. A slight improvement would be to contrast with sibling tools explicitly.

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