session_set_nodal_values

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

With no annotations, the description carries the full burden and does well: it discloses the deferred-effect timing (next session_advance), that writes go only into the live in-memory model with disk files unchanged, and that omitted fix leaves fixity untouched. It does not discuss permissions or error behavior, but the mutation model is clearly conveyed.

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?

Dense, front-loaded prose with every clause carrying information: target selection, value typing, fixity semantics, effect timing, and persistence scope. No redundant restatement of the tool name or 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?

An output schema exists, so return values need not be described, and the description covers targeting, value formats, fixity behavior, and when the change materializes. Nothing an agent needs to call this mutation correctly is missing.

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%, so the description must compensate, and it does for the key parameters: value can be a scalar or [x, y, z] for vector variables like DISPLACEMENT/VELOCITY, fix accepts a boolean or a 3-boolean list with omission meaning unchanged, and node_ids/model_part define the target set. session_id is left unexplained, which keeps this from a 5.

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 precise verb+resource (assign a nodal solution-step value) and defines the two targeting modes: explicit node_ids, or all nodes of model_part when node_ids is omitted. It also names the live-model scope versus on-disk files, which helps distinguish it from the file-oriented mdpa_set_nodal_data sibling.

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?

Explicitly says it takes effect from the next session_advance and gives concrete use cases (add a support, pin a temperature, perturb state mid-run), which tells the agent when to reach for it. It does not name alternative tools like mdpa_set_nodal_data, so sibling routing is implied rather than stated.

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