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

Annotations already declare readOnlyHint=true, openWorldHint=false, and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful semantics beyond that: key_expires_at is null when the key never expires, feed_ready is false while the Growth Snapshot deep scan builds, and credits appear only once metering is live. It stops short of describing failure behavior for an invalid key.

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?

It is a single dense sentence that front-loads the core purpose and then qualifies each returned field with a parenthetical. Nothing is wasted, though the stacking of nested parentheticals makes it slightly harder to scan than a short bulleted structure would be.

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 no output schema and no parameters, the description carries full responsibility for explaining return values, and it does so field by field, including edge-case semantics for null expiry and false feed_ready. An agent has enough to call the tool and interpret the response correctly.

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 baseline is 4. The description correctly implies a no-argument identity call and spends its words on outputs instead, which is the right allocation for a 0-param 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 states a specific verb and resource ('Confirm the AfterLaunch key works') and then enumerates exactly what the call reports: product run, scopes, tier, trial_ends_at, key_expires_at, onboarding, and credits. No sibling tool covers identity/credential verification, so an agent can distinguish this from the get_*/list_* family without reading the schema.

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 by 'Confirm the AfterLaunch key works' — an agent infers this is a credential/setup check — but there is no explicit when-to-use, when-not-to-use, or named alternative. Given the tool is unique among siblings, the omission is minor, but the guidance remains implicit rather than stated.

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