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

No annotations are provided, so the description carries the full burden. It usefully discloses that reserved fields are automatically filtered out and that project_key falls back to the global tenant_id. However, it does not explain whether existing fields are replaced or merged, potential permissions, or error behavior, leaving gaps for a mutation tool.

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 well-structured with a clear opening sentence and a formatted Args/Returns section. It is slightly lengthy due to listing all reserved fields, but each sentence adds meaningful detail without redundancy.

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 3-parameter update tool with an output schema, the description is fairly complete: it covers all inputs, the return type, and key behavioral quirks. The main omission is the exact semantics of field replacement (e.g., whether unspecified fields are removed), which is important for a destructive-feeling update operation.

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?

The description provides thorough parameter explanations that go beyond the sparse input schema: it details the fields array with SchemaField properties, explains the project_key fallback, and lists the reserved field names. With 0% schema description coverage, this fully compensates.

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 clearly states the tool updates schema fields, using the verb 'update' with a specific resource. The phrase 'step 2 of schema field management' provides context and distinguishes it from siblings like create_schema and get_schema.

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?

It indicates this is part of a multi-step schema field management process and describes the expected input (existing + new fields). However, it does not explicitly state when not to use this tool or directly name alternatives, leaving some ambiguity.

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