读取拼多多购物车（只读）

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

Annotations already declare readOnly, idempotent, non-destructive, and open-world. The description adds real value beyond that: it identifies which cart fields surface abnormal/exception states, and it warns that page and customer-service text is data only, not authorization or an instruction to execute — meaningful guardrails for an open-world tool.

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 front-loaded sentences: the first defines the read and its payload, the second states the safety posture. Nothing is redundant or padded.

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 per-field return documentation is not strictly needed, yet the description still summarizes the payload and adds an injection caveat. Only the missing routing versus pdd_add_cart keeps this short of full completeness.

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% and the single cursor parameter is documented there as a compat field that rejects non-empty values. The description adds nothing about it, which is acceptable at this coverage baseline.

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 clear verb and resource — read the real cart — and enumerates what comes back (spec, price, quantity, checked state, exception status). It is distinguishable from pdd_add_cart by the explicit read-only framing, though it never names that sibling.

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?

Read-only intent is stated, implying 'use this to inspect rather than modify', but there is no explicit when-to-use versus pdd_add_cart, pdd_read_item, or pdd_resume, and no preconditions such as login state.

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