get_source_schema

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context beyond annotations: it is 'not separately rate-limited' and it reads a registry profile built by register_source, which clarifies the data source and operational cost. It does not describe the return format, but with no output schema and a read-only profile read, the description carries enough weight.

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 three sentences with no filler. It front-loads the core purpose and content, then immediately gives the sibling distinction, then adds safety/rate-limit context and a lookup pointer. Every sentence earns its place.

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 single-parameter read-only tool with full schema coverage and rich annotations, the description is complete. It tells the agent what the tool returns, how it differs from the closest sibling, how to obtain the required parameter, and that it is not separately rate-limited. Nothing needed to call it 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 100%, so the schema already documents source_id as 'Source ID from list_sources.' The description reinforces this by saying 'Use list_sources to find source ids,' which adds a practical lookup instruction beyond the schema. Since the schema fully covers the single parameter, the description's added value is modest but real.

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 states a specific verb ('Get'), a specific resource ('full schema for a specific registered source'), and enumerates the content (column types, cardinality, fill rates, formula relationships, detected join keys). It also explicitly distinguishes itself from the sibling get_data_schema, so an agent can tell them apart without opening schemas.

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 explicitly says when to use this tool ('reads the source-registry profile built by register_source') and when not to ('use get_data_schema for the dataset-level schema view of the connect_data flow instead'). It also tells the agent to use list_sources to find source ids, which is a clear prerequisite.

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