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

Adds substantial behavior beyond the annotations: the spec is validated and its tests executed, failures return errors and suppress the card entirely, and the caller must re-send the whole spec to modify. It also states an output-usage rule ('Quote numbers from the result, never compute them yourself') that the agent could not infer from readOnlyHint/idempotentHint alone.

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, then usage triggers, then spec requirements, then failure semantics — a sensible order with no filler sentences. It is dense and long for a two-parameter tool, but nearly every clause carries operational information.

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?

With no output schema, the description carries the burden of explaining return behavior and does so: success yields a card, failure yields an error list and no card. Combined with the prerequisite, the spec contents, and the revision loop, an agent has everything needed to call this correctly on the first attempt.

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, and the description earns above that by unpacking what a complete ModelSpec must contain (schema, derivations for every computed field, viewDefinition, given/expect tests) and by framing `inputs` as the card's current values on re-render. The one gap is the canonical-path syntax for `inputs`, which the description leaves to the schema example.

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 — 'Show the user a Valem model as an interactive card they can edit in the chat' — and immediately characterizes the artifact (a form with computed fields checked by a deterministic engine). This clearly separates it from siblings like create_model, get_model_info, or validate_spec without needing to name them.

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?

Gives an explicit trigger list ('calculator, quote, budget, planner, pricing or any model with inputs and computed results') plus a prerequisite ('call valem_spec_guide first') and a revision workflow ('call again with the whole revised spec and the current inputs from the card'). It stops short of naming sibling alternatives or a when-not-to-use condition, which keeps it out of 5 territory.

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