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

Annotations already declare readOnly/idempotent/openWorld, so the bar is lower, yet the description adds real value: it states what is returned (per-step cost bounds in USD, the pinned card_revision, chain totals) and guarantees no invocation or charge. This is genuine behavioral context beyond the structured fields.

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 key frame ('Pre-price an invocation chain BEFORE spending money') and three dense sentences that each carry information (step forms, return contents, usage). Slightly packed but nothing 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?

No output schema, but the description compensates by naming the return payload (cost bounds, card_revision, totals) and the enforceability of the estimate. For a one-parameter nested tool this covers what an agent needs to call and interpret it, leaving only minor details like chain-size limits unstated.

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% (baseline 3), but the description adds conceptual meaning: each step is either a concrete offering or a `select` query that picks the best-ranked match, plus expected input/output tokens. This explains the dual-mode `steps` structure better than the schema alone, and ties `select` to search_offerings semantics.

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: 'pre-price an invocation chain BEFORE spending money,' with the scope (chain, not single offering) and the two step forms made explicit. An agent can distinguish this cost-estimation tool from search_offerings/get_offering without opening either 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?

Gives clear when-to-use: 'compare routes or budget a multi-model pipeline,' and notes the safety condition ('nothing is invoked or charged'). It references search_offerings implicitly ('same as search_offerings') but does not name a specific alternative for actually invoking the chain, so no explicit when-not routing.

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