switch_tab

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

Annotations already flag readOnlyHint=false and openWorldHint=true, so the mutation profile is covered. The description adds one genuinely non-obvious behavioral fact — that new tabs and popups become active automatically, making an explicit switch unnecessary. It does not cover what happens with an out-of-range index or how session scoping behaves.

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 with zero waste; the core action is front-loaded and the 0-based caveat is attached directly to the parameter it governs.

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 simple two-parameter focus-switching tool with no output schema, this is close to sufficient — action, indexing convention, and auto-activation behavior are all present. The only gap is any explanation of the required `session_id`.

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 0%, so the description must carry the load. It meaningfully clarifies `index` as 0-based, which the schema does not, but says nothing about `session_id` (how a session is identified or obtained). Half the parameters remain undocumented in both places.

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 ('Make ... the active tab') and resource ('tab `index`'), and specifies the 0-based indexing convention. An agent can distinguish it from open_session/close_session without opening a schema.

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?

Usage is implied by the purpose (switch focus among tabs within a session) but the description never says when to call it versus a sibling like open_session or navigate, nor any preconditions. The note about popups auto-activating hints at when it is NOT needed, which is a partial but real signal.

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