pane_focus

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

Annotations already declare readOnlyHint=false, idempotentHint=false, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description usefully adds that identity is verified before dependent operations, but it never describes what changes on focus, that a mismatch aborts the write, or how timeout_ms governs failure.

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?

One front-loaded sentence with no filler. The second clause is compressed to the point of jargon ('widget reference identity') but does carry real information about the guard behavior.

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-required-parameter mutating tool with no output schema, the description covers the purpose and the precondition check but omits failure semantics (layout mismatch, timeout) and doesn't explain the extra optional parameter, leaving the agent to infer behavior from the schema alone.

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 only 50%: target_id and expected_layout_id are documented in the schema, while index and timeout_ms are not. The description only loosely covers index ('focus a pane by index') and says nothing about timeout_ms or the interaction between index and the identity checks, so it does not fully compensate for the gap.

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?

It states a specific verb and resource ('Focus a pane by index') and adds a guard clause about verifying widget reference identity. An agent can tell what the tool does, but it does not contrast itself with pane_set_layout/pane_set_symbol/pane_set_timeframe, which also target panes.

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 phrase 'before dependent operations' implies this is a precondition step, which is useful implied usage guidance. However, there is no explicit when-to-use/when-not guidance or named alternative among the many pane_* siblings.

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