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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so safety basics are covered. The description adds genuinely useful context for this API: it explicitly says the call does not spend credits, which matters in a toolset where enrichment calls do consume credits.

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?

Two short sentences, front-loaded with the purpose and followed by the returned fields. The opening 'Get subscription status.' largely restates the title/annotation, so one small redundancy, but nothing else is wasted.

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 input parameters, no output schema, and full annotation coverage, the description carries its part: it names the returned fields (plan, billing cycle, credit caps) so the agent knows what it gets back. Only the relationship to sibling account/usage tools is left implicit.

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 says nothing about inputs and avoids inventing parameter details that do not exist.

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 ('Get subscription status') and enumerates the returned content — plan details, billing cycle, credit caps — which separates it from siblings like dealmachine_usage (consumption stats) and dealmachine_get_mail_wallet_balance (mail credits only). It never names those siblings, so differentiation is implicit rather than explicit.

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 only implied by 'your current' — an agent can infer this is the account-level subscription lookup, but there is no explicit when-to-use guidance and no stated boundary against dealmachine_account or dealmachine_usage.

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