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

Annotations already declare readOnly/openWorld, so the description focuses on what those don't cover: the window includes today, limit is capped at 500, and the returned row sum is not the grand total because of truncation. That truncation warning is genuinely valuable and hard to infer elsewhere; missing is any statement of sorting or ordering of rows.

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-loaded with the result shape, then the time window, then the truncation caveat, then the workspace note — each sentence carries new information. The phrasing is compressed to the point of terseness (telegraphic German), but nothing is redundant.

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?

An output schema exists, so return values need not be spelled out, and the description covers the window, truncation behavior, and the fallback for totals. The only real gap is which sibling to prefer for configured-vs-performed key events, plus row ordering.

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 0%, so the description must carry the load and largely does: it defines the days window semantically, gives the 500 hard cap on limit, and explains workspace as a slug that may be omitted when only one workspace exists. It omits the default values (7, 50/null) that the schema declares, and gives no units or format examples for workspace.

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?

States the concrete output shape: conversion/key events with count and value per eventName. An agent can tell this apart from the config-oriented ga4_list_key_events. The verb itself is implied rather than stated (no explicit 'list/retrieve'), which keeps it just 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?

Explicitly routes the agent to ga4_report with metrics=['keyEvents'] and dimensions=[] when overall totals are wanted, which is the key distinction. It does not, however, contrast against ga4_list_key_events or explain when this tool is preferable to a generic ga4_report call.

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