Open the map pane

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

With no annotations, the description carries the full burden and does so richly. It discloses that opening is not visibility (`Generated does not mean visible: this server cannot open or observe the desktop side panel`), that it never closes a pane, that the reply indicates whether a pane actually reported itself in, that agent exec PTYs cannot be attached by id, and that retry should only happen after environment changes or user request.

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?

The description is long but almost every sentence carries operational value—surface routing, retargeting semantics, failure policy, platform support. It is organized by surface then general behavior, though it leads with the web-terminal edge case rather than the default terminal workflow, so it is not perfectly front-loaded.

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 tool with three optional parameters, no output schema, and no annotations, the description covers invocation triggers, parameter semantics, failure handling, retry rules, supported terminal environments, and limitations. It gives enough context for an agent to decide when to call it and what to expect from the reply.

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?

Although schema coverage is 100%, the description adds significant meaning beyond the schema: it explains the page slug convention and the pitfall of omitting it (opens last-written page), constrains window to explicit user requests for a separate window, and elaborates each surface enum value into concrete workflows and limits. This materially helps correct invocation.

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 clear verb and resource: it opens or retargets the map pane beside the conversation and can show a specific page. It distinguishes itself from siblings by detailing surfaces, the `pane: CLOSED` trigger, and retargeting behavior, so an agent can tell it apart from `mmap_view` or `mmap_update` without guessing.

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?

Gives explicit when-to-use guidance: call whenever a result says `pane: CLOSED`, do not ask permission first, and use it to show a requested page when a pane is already open. It also maps each surface to a specific scenario — web-terminal for Codex desktop, codex-terminal for the native host terminal, markdown for document panels, and web for interactive maps — with clear exclusions like not launching the watcher or typing into the terminal.

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