action_add_s3

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

With no annotations provided, the description carries the full burden. It discloses the side effect (adding a connection and providing ctx variables) and adds a clear behavioral contract: never call list_buckets, and verify read/write via put_object/get_object with content comparison and delete_object in ctx.S3_DATA. This goes well beyond the schema, though it omits any mention of auth requirements or reversibility.

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?

Two sentences, both substantive. The first states purpose and resulting context variables; the second provides critical safety and verification guidance. No filler, no repetition of schema content, and the most important constraints are front-loaded.

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 setup-style tool with no output schema and no annotations, the description is remarkably complete. It explains what the tool does, what state it creates, and how to verify the connection works. The only missing information, such as return value or auth prerequisites, is mitigated by the explicit verification procedure.

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 only parameter, endpoint, already has 100% schema description coverage with a regex, rule about segments, and an example. The description adds the context that the endpoint is the target of the S3 connection, but it does not need to repeat the schema details. Baseline 3 is appropriate given the schema already documents the parameter fully.

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 names a specific verb and resource: 'Add a bucket-scoped S3 connection to an endpoint's context.' It also lists the concrete context variables provided (ctx.S3_CLIENT, ctx.S3_DATA, ctx.S3_WEB, ctx.S3_PUBLIC), which makes the tool's function concrete and distinguishes it from sibling tools like action_add_milvus or action_add_postgresql.

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 context for use is clear: it is for adding an S3 connection to an endpoint. However, the description does not explicitly say when to choose this tool over alternatives or when not to use it. The 'Never call list_buckets; verify read/write...' guidance is operational, not tool-selection guidance, so it only partially covers this dimension.

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