daysOne game’s players day by day (New York days, newest first): the average, peak and low, visits that day, and what happened (updates, events). Free shows the last 7 days; Pro shows every day since tracking began on Sep 27 2026 (up to 60).
| Name | Required | Description | Default |
|---|---|---|---|
| days | No | How many days back, 1 to 60 (default 14; Free sees 7) | |
| game | Yes | The game: its name (like "grow a garden"), its universe id, or its roterminal.co/g/ link |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the safe read-only, idempotent, closed-world profile. The description adds genuinely new behavioral context beyond them: entitlement gating (Free = 7 days, Pro = all days since Sep 27 2026, capped at 60) and the newest-first ordering of results.
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, front-loaded with purpose and result shape, followed by the tier limits. Every clause carries information; only the parenthetical tier detail could be trimmed.
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 only two parameters, no output schema, and annotations covering safety, the description supplies what is needed: what the rows contain and how many days are visible per tier. Edge cases and error behavior are absent, but nothing essential to calling 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 both parameters, including the 1–60 range and default. The description adds the ordering of the returned days and the Free-tier constraint on the window, but no format or syntax detail beyond the schema, so baseline 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?
States a specific resource (one game's players) and a specific shape of output (day-by-day average, peak, low, visits, events), which is enough to tell it apart from siblings like trends, charts, and compare. It does not explicitly name which sibling to use instead, so it falls 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?
Usage is implied: the description explains the tier-dependent window, which gives context for when the tool is useful but never states when to prefer it over trends/compare/charts or what preconditions apply. No explicit when-not guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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