create_block

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

Annotations provide only readOnlyHint=false and destructiveHint=false (which the description matches — no contradiction). The description shoulders the behavioral transparency burden richly: fields[0] is always read-only, enum fields get an auto-injected whitelist validation formula, date/datetime values get converted to numeric form, and the target sheet is auto-created if missing. These are non-obvious behaviors the agent needs to know.

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?

The description is front-loaded with the core purpose and organized with clear bullets for field types, making it scannable. It is somewhat long, but every sentence earns its place by adding functional detail (e.g., enum validation behavior, editability routing). Slightly verbose in places but justifiably so.

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?

Despite having nested objects, 5 parameters, and no output schema, the description is thorough: it covers all field types, prerequisites, inference rules, and side effects (auto-create sheet, auto-injected validation, read-only row-key). The separate-rules-via-set_field_rule note prevents false expectations about this tool's scope. Nothing critical is left unexplained.

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, but the description adds substantial value beyond the schema: it explains field type semantics (for each type), how type inference works from initial_rows values, the enum_id prerequisite, ISO string conversion for dates, and the block ref name's formula usage. The description meaningfully enhances parameter understanding.

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?

The description opens with a specific verb+resource statement: 'Create a structured block (table) on a sheet.' It clearly defines the scope (structure + initial rows only), distinguishes from siblings (create_sheet, set_field_rule), and explains the block ref name's role. The purpose is unambiguous and well-differentiated.

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 states when to use ('this call only declares structure + initial rows') and when not to use ('Rules are set separately via set_field_rule'). It documents prerequisites (define_enum_set for enum types), explains the auto-create behavior for missing sheets, and clarifies how field_type is inferred when omitted. This is exemplary usage guidance.

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