Read the referral report

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavior: UTC day boundaries, the 92-day cap, the default window, and that a workspace without referrals enabled returns an explanatory message rather than an error. It says nothing about auth or rate limits, so not a 5.

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?

Sentences are front-loaded with the read-only marker and the report definition, then constraints, then the edge case. No filler and nothing repeated from annotations unnecessarily.

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 two-optional-parameter read tool with no output schema, the description covers what is returned, how it is ordered, default window, maximum span, timezone, and failure-mode behavior. An agent can call it correctly without further inference.

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 100% so the baseline is 3, and the description earns the bump by supplying the omitted default ('the last 30 days') and the maximum span (92 days), neither of which the schema states for the unbounded `from` parameter. It also fixes the timezone semantics (UTC days), which the schema's date-time format leaves ambiguous.

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 verb+resource ('read the referral report') and then defines the report's shape: per referral code, the taps that carried it and the referred installs, ordered most-conversions-first. That level of specificity clearly separates it from siblings like get_analytics or get_top_links.

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?

Gives concrete operating context: a date range, a default of the last 30 days, and a hard 92-day cap per call. It also notes the graceful path when referrals are not enabled. It does not name an alternative tool or state when to prefer get_analytics over this, so it falls short of a 5.

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