open_layout

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 well: read-only access, session expiry on inactivity, the requirement to close sessions, and the cross-cutting fact that the returned session_id is mandatory for all other tools. It doesn't cover permission failures or error conditions, keeping it out of 5 territory.

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?

Front-loads the critical 'Call this first' instruction, then lifecycle, then a compact Args block. Every sentence adds operational value with no filler.

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 session-creating entry-point tool, the description covers purpose, ordering, lifecycle, cleanup, and all three parameters. An output schema exists, so return-value detail is unnecessary, and the one key return field (session_id) is already called out.

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 0%, so the description must compensate, and it does fully: path is an absolute path restricted to .gds/.oas, top_cell specifies the default with a stated fallback (alphabetically first top cell), and format resolves ambiguity when the extension is unclear. Each parameter gains meaning absent from the bare 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 (open), resource (GDS/OASIS layout), and mode (read-only), plus the side effect of starting a session. 'Call this first' immediately distinguishes it from every sibling tool, which all depend on the session it creates.

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 clear ordering guidance ('Call this first'), the lifecycle rule (sessions expire after inactivity), and names close_session as the terminating counterpart. It stops short of describing when-not to use it or how it pairs with specific downstream tools, so it falls just below the top.

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