cf_login

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

With no annotations, the description carries the full behavioral burden and largely fails: it does not say that authentication mutates session state, whether credentials are cached/stored or expire, what happens on failure, or that the env-var fallback applies to specific variable names. Only the credential-source fallback is disclosed.

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 short sentences, zero filler, with the core action front-loaded before the conditional fallback. Nothing is repeated from the schema or title.

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 stateful authentication tool with zero annotations, no output schema, and five optional parameters, the description is thin: it omits which environment variables are consumed, whether a session token is persisted, and how org/space relate to the separate cf_target tool. An agent would need outside knowledge to call this correctly.

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 org, space, password, username and apiEndpoint are already documented in the schema; baseline 3 applies. The description adds only the env-var fallback for the credential parameters, not which variables are read or how org/space interact with targeting.

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?

States a specific verb (Authenticate) and resource (Cloud Foundry) with the credential source, so an agent immediately knows this establishes a CF session rather than targeting or listing anything. It does not explicitly contrast itself with cf_target/cf_get_target, but the purpose is unambiguous within the sibling set.

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 second sentence gives a fallback rule — use environment variables when no parameters are supplied — which is real usage guidance. However, it never states when this must be called relative to cf_target or other CF commands, nor any prerequisites (API endpoint required first?), leaving the sequencing to inference.

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