Add a ready-made arrangement

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

Annotations already declare the non-destructive, non-idempotent, closed-world profile, but the description adds genuine behavior: blocks reflect live records, show an empty-state message, contain no example text, and the notable failure mode that a missing workspace type causes nothing to be added with instructions to create it. This goes meaningfully beyond the annotations.

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?

Purpose is front-loaded and the following sentences each carry distinct content (behavior, population rule, failure mode). The phrasing is somewhat convoluted ('for a job the person named'), costing some crispness, but there is little true filler.

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 mutation tool with annotations and no output schema, the description covers what is created, live-record behavior, empty state, and the missing-type failure path. Only the exact return shape is left unaddressed, which is minor since it says the result describes each block.

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% and the schema already documents the name enum and the fills object. The description echoes the catalogue and 'what a block lists comes from records and cannot be filled in' but adds no syntax or format detail beyond the schema, so baseline 3 is appropriate.

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 ('add a whole arrangement of blocks... in one call') and ties it to the catalogue, which is concrete. It distinguishes itself from create_canvas/arrange_canvas only implicitly via 'laid out as the catalogue says', so it stops short of a clean sibling contrast.

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 a useful related-tool instruction ('To put things on it, create the records the person gave you with create_record; never invent any'), which is real when-to guidance for populating. But it never says when to pick this over arrange_canvas, create_canvas, or add_component, so selection among siblings is left to inference.

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