read_data_by_identifier

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

No annotations are provided, so the description bears the full burden. It does disclose a genuine behavioral trait, the one-at-a-time restriction for DIDs outside the ECU config, which is non-obvious and useful. However, it omits anything about session/security prerequisites and does not state the failure behavior when a DID is unsupported by the ECU.

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?

Three short sentences, front-loaded with the service name and immediately followed by the parameter format and then the constraint. Nothing is wasted, though the leading '0x22 ReadDataByIdentifier' is largely a restatement of the tool name plus the service code.

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 return values need not be described. For a UDS diagnostic read, though, an agent still needs to know about session and security-access preconditions, and the description covers neither, leaving a meaningful gap in operational 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 0% for the single 'dids' parameter, so the description has to carry the meaning and partially does, giving a hex-string example ("F190", "F18C") and a batching caveat. It does not specify accepted DID length or case/prefix expectations, so it only partly compensates for the empty schema.

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 names a specific verb and resource and ties it to the UDS service ID 0x22, which lets a UDS-literate agent distinguish it from siblings like write_data_by_identifier and read_dtc_information. It stops short of explicitly contrasting against the nearest sibling, but the read/write split is clear.

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 only usage guidance is an operational constraint ('DIDs not known to the ECU config must be read one at a time'). There is no statement of when to use this versus send_raw or read_dtc_information, nor any mention of preconditions such as an active diagnostic session or security access.

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