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

Adds substantial context beyond the annotations: it discloses that the new code replaces the previous one, that it is valid for 30 days, that it can be shared as text or a URL, and that use of it produces a friend request requiring approval. The annotations only carry safety flags, so this lifecycle detail is genuinely additive.

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 core action and constraints, and every sentence serves a purpose (replacement, validity, sharing, downstream effect, gating). The middle sentence describing the sharing/approval flow is a little long but still earns its 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?

An output schema exists, so return values need not be explained, and the description fully covers the lifecycle: creation, replacement, validity, sharing mechanism, and the resulting friend request. Nothing an agent needs to invoke 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?

The tool takes zero parameters, so the schema carries no semantics to add. Baseline for a parameterless tool is 4; the description correctly adds no redundant parameter talk.

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 and resource ('Make a fresh friend code') and immediately scopes it with the replacement behavior and 30-day validity. It also implicitly distinguishes the creation side from the redemption side (redeem_friend_code) by describing who creates vs. who uses the code.

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 an explicit gating condition — 'Only create one when they ask' — which prevents over-eager invocation, and describes the downstream flow that motivates sharing it. It does not, however, name an alternative tool or spell out when-not-to-use cases beyond the request condition.

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