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

Annotations already cover safety (readOnly, idempotent, non-destructive), yet the description adds substantial process detail beyond them: ISO-TP reassembly, request/response pairing including 0x78 responsePending, P2/P2* timing, session and security-access tracking, RequestDownload/TransferData reconstruction with CRC32, and DID extraction. This tells the agent exactly what the analysis performs.

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-loads the purpose in the first sentence, then packs the accepted formats and analysis steps into a single dense second sentence where every clause names a concrete capability. No filler or restated boilerplate.

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 exists, and the description compensates by stating the return: a root-cause finding with the supporting frames plus an interactive timeline. Combined with the input-format guidance, an agent has everything needed to call and expect results.

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%, so the baseline is 3, but the description adds real value by mapping formats to parameters: text formats (candump, ASC, TRC, CSV) go in 'trace' or 'file', while binary formats (BLF, pcap/pcapng, MF4) require 'file' upload. That clarifies which parameter each format belongs in.

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: 'Analyze a whole CAN trace of a UDS diagnostic or flash session and say what went wrong.' The scope word 'whole trace/session' distinguishes it from the frame-level decoders (decode_isotp, decode_uds) in the sibling set.

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?

Implies usage by scoping to an entire diagnostic/flash session rather than individual frames, which steers agents away from the single-frame decoders. However, it never explicitly names an alternative or states when NOT to use it, so routing rests on inference.

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