sx_save_or_update

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

With no annotations, the description carries the full burden. It discloses that the tool is a mutation (save/modify) and reveals a non-obvious guard behavior: the operation is silently ignored unless environment conditions are met. This is valuable behavioral info. However, it does not mention side effects, return values, or error behavior, which would make it more complete.

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 extremely concise: two sentences, no filler. The primary function is stated first, followed by the essential guard condition. Every word earns its place, and the structure is front-loaded with the action before the prerequisite detail.

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 write operation with no annotations, no output schema, and one complex object parameter, the description is incomplete. It omits details about bill structure, expected behavior on success/failure, and how to interpret the result. Agents lack sufficient guidance to construct a valid bill payload or handle the response 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?

The schema covers 0% of the parameter meaning; the only parameter 'bill' is an open object with additionalProperties allowed and no description. The description does not explain what the bill structure should contain, which fields are needed, or any formatting rules. With such low schema coverage, the description was expected to compensate but fails entirely.

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 clearly states the tool's purpose: 'save/modify document' (保存/修改单据), which is a specific verb plus resource. It also identifies the official method (saveOrUpdate). While it doesn't name a sibling to differentiate from, the write nature is distinct from the many read/list siblings, and the core action is unambiguous.

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 provides important usage context: it is rejected by default by a read-only guard and requires specific environment settings (SX_READONLY=false and SX_ALLOW_WRITE_ACTIONS containing saveOrUpdate) to actually execute. This tells an agent when the tool will work, but it does not explicitly say when to prefer this over alternatives (e.g., sx_submit or sx_operation) or provide exclusions.

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