Show or switch E*TRADE environment

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

With annotations only declaring readOnlyHint=false, idempotentHint=true and destructiveHint=false, the description adds real behavioral context: sandbox and production hold separate keys AND separate access tokens, switching never mixes credentials and never invalidates the other side. That is exactly the non-obvious operational detail an agent needs before flipping environments.

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?

Sentences are front-loaded with the core action, then the no-arg behavior, then the credential-isolation rationale, then the sandbox caveat. No filler or repetition; every sentence carries distinct information.

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-optional-parameter tool with annotations already covering the safety profile and no output schema, the description covers both call modes, the resulting state change, and the data-quality caveat about sandbox. An agent has everything needed to invoke it 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 coverage is 100% and the schema already explains omitting the parameter, so baseline is 3. The description adds meaning beyond the schema by stating what an omitted argument actually reports (which key pairs are configured and which is in use), which clarifies the effect of the parameter's absence.

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 and resource ('Show or switch which E*TRADE environment is active') and immediately distinguishes the two modes by their arguments. It is clearly separable from siblings like etrade_connect or setup_credentials, which handle connection setup rather than environment selection.

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 gives explicit conditions for both invocation modes ('Call with no argument to see... pass environment to switch') and directs the agent to use production for real figures since sandbox returns canned data. It does not, however, name a sibling alternative for related status questions (e.g., setup_status / provider_status), leaving some routing to inference.

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