Read GRAPH Step or Transition Context

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds real behavior on top: the read is against the live block, exactly one block is returned, and reused step numbers are disambiguated by sequence. It omits timeout/error behavior and any mention of result volume despite a limit parameter.

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 tight sentences, front-loaded with the action and return content, then the disambiguation rule, then the exclusions. No filler and no restatement of the title.

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 9-parameter tool with no output schema and only annotation-level safety coverage, the description explains the core read semantics well but leaves most parameter semantics and failure behavior to the schema. Adequate to call correctly in the common case, incomplete for the optional parameters.

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 0% across 9 parameters, so the description carries the full burden, yet it only indirectly explains step, transition, and sequence (via the disambiguation note). processId, name, number, softwarePath, limit, and timeoutMs get no meaning from the description at all, leaving the required pair unexplained.

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?

Specific verb plus resource ("Read one exact live GRAPH block") and an explicit statement of what comes back for each case (a step's exits vs. a transition's predecessor/successor steps, actions, interlocks, Boolean guards). It also fences itself off from adjacent tools via the negative scope sentence, so an agent can distinguish it from tia_get_current_block or tia_read_block without opening schemas.

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 closing sentence gives clear when-not guidance (no UI navigation, project write, scheduler simulation, PLC runtime monitoring), and "Sequence numbers disambiguate reused step numbers" tells the agent how to handle the ambiguous case. It stops short of naming a specific alternative tool for those excluded scenarios, so it is clear context without explicit routing.

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