bc_lookup

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

With no annotations provided, the description carries the full burden and does so thoroughly. It discloses that the operation is non-mutating, opens the lookup form, always cancels without selecting, and leaves the source page field unchanged. It also states that lookupCustom=true results in a clear error, which is valuable behavioral context.

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 a one-sentence purpose definition, then organized into usage, exclusions, and workflow. Every sentence contributes practical value, and examples clarify the intended use without padding.

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?

The description covers purpose, usage, exclusions, workflow, side effects, and error behavior, but since there is no output schema, it stops short of specifying the exact shape of returned result rows beyond 'candidate values' and 'result rows.' This is a minor gap for a tool whose primary output is a list of rows.

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 100%, so the baseline is 3. The description adds extra meaning beyond the schema by explaining the workflow prerequisites (pageContextId from bc_open_page), how the search string filters via BC's native search, and the maxRows default/cap. This enriches parameter understanding beyond raw schema text.

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 and resource: 'Enumerates candidate values for a related-table (FK) field by invoking BC's built-in Lookup.' It clearly distinguishes bc_lookup from siblings like bc_write_data and bc_read_data by scoping it to lookup candidate enumeration on open pages.

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 description gives explicit when-to-use guidance ('Use this when you need to see valid choices for a field before writing it'), plus clear exclusions: not for option/enum fields, not for fields where isLookup is false or absent, and not for lookupCustom=true fields. It also provides a concrete workflow sequence.

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