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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false), so the description's job is lighter. It adds useful scope context: 'Stores layout only; does not place trades.' It does not disclose duplicate-name behavior or error/repeat-call semantics, but the core behavioral trait is clear.

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?

Three tight sentences, front-loaded with the action and scope, followed by the sourcing tip and the scope clarification. Every clause earns its place with no 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?

With an output schema present, return values need no explanation, and the two required parameters are covered by the schema. Purpose, config sourcing, and the 'stores layout only' scope are all present, so an agent has everything needed to call 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 both parameters are fully documented in the schema, so the baseline is 3. The description reinforces that 'configuration' is a serialized layout JSON string and points to list_terminal_tabs as a source, but adds no syntax or format detail beyond the schema.

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 and resource ('Create a terminal tab') plus scope ('for the signed-in user') and the input form (saved layout JSON serialized as a string). It also differentiates from siblings by naming list_terminal_tabs as the preferred config source and clarifying it 'does not place trades', disambiguating a create_tab write from any trading action.

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?

'Prefer copying an existing tab configuration from list_terminal_tabs' gives clear, actionable guidance on where to source the configuration. It stops short of stating when to use this versus update_terminal_tab (e.g., new tab vs. modifying an existing one), so no explicit exclusion is provided.

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