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

With annotations covering the safety profile (readOnly, idempotent, non-destructive), the description still adds substantial behavioral detail: the specific report contents (SF/FF/CF/FC frame types, BS/STmin flow control, sequence-number errors, interrupted messages, padding, N_Bs/N_Cr timing warnings) and the condition under which timing analysis appears. It does not describe behavior on malformed or truncated input, which is the main remaining gap.

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 dense sentences with no filler, front-loading the core reassemble-then-decode action before output details. The second sentence is a long enumeration but each item earns its place by naming a distinct diagnostic class.

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 3-parameter tool with no output schema, the description carries the return-value burden and does so by enumerating the diagnostic categories reported, plus both accepted input formats. It is nearly complete; only preconditions for timing analysis depth and malformed-input handling are left implicit.

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 description coverage is 100%, so the meaning of each parameter (frames, padding, decodeUds) is already documented in the schema; the description only reinforces that timestamped input unlocks timing warnings. Baseline 3 is appropriate since the schema does the heavy lifting.

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 compound action (reassemble ISO-TP messages from CAN frames per CAN id, then decode as UDS) with the exact protocol standard, which unambiguously separates it from decode_uds (single payload) and build_uds_request (constructs requests). Verb+resource+scope are all present in the first clause.

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 implies when it applies by defining the accepted inputs (frame list or candump dump) and the precondition for timing warnings (timestamps in ms), but it never explicitly routes the agent between this tool and its siblings decode_uds or build_uds_request. Usage is inferable rather than stated.

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