get_savings_card

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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive hints, and the description adds substantial behavior beyond that: it clarifies the output shape, warns that the MCP Apps interactive card is not a substitute, instructs the agent to still write the codes, limits saving options to one, and imposes accuracy constraints about insurance, pricing, and lowest-price claims.

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?

The description is long but every section earns its place: usage triggers, parameter meanings, return contents, and agent rules. It is front-loaded with the primary purpose and structured into readable paragraphs. Slight redundancy exists in the output enumeration, but it compensates for the absence of an output schema.

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 tool with no output schema and only minimal parameter schemas, the description is exceptionally complete. It covers return values, side-channel presentation behavior, usage constraints, pricing caveats, and all three parameters. An agent has enough context to invoke it correctly and handle its results appropriately.

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 0%, so the description carries the full burden. It explains drug as a slug from search_drugs that may add a price, locale as a language code with a defined fallback, and channel as a link-tagging value. Each parameter is meaningfully described, though channel could be more precise about expected values.

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 ('Get'), a specific resource ('the free FineRx discount card'), and enumerates the concrete outputs: codes, usage steps, and saving methods. It is clearly distinguishable from siblings like search_drugs or compare_prices.

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?

The description explicitly names three trigger conditions: after quoting a FineRx price, when asked about paying less, or when the card is requested by name. It does not explicitly contrast with email_savings_card or other siblings, but the conditions are concrete enough for an agent to select this tool correctly.

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