load_session

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

Annotations already flag destructiveHint=true and readOnlyHint=false, and the description adds the concrete meaning of that: everything currently loaded is replaced. It also discloses an important side effect beyond the annotations — name collisions when merge=True — which the schema does not mention.

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 core action in one sentence, then spends the remainder on the non-obvious merge behavior. No filler or 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 destructive/replace semantics plus the merge caveat cover the main risks. Minor gaps remain, such as error behavior for a missing or invalid .pse path.

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% so the baseline is 3, but the description adds genuine meaning to merge: it explains the use case (side-by-side scenes) and the collision risk with identically named objects, which the schema's one-line definition does not convey.

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: restores a PyMOL session from a .pse file. That is clearly distinguishable from siblings like save_session, load_structure, and load_map without needing to open the 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?

Explains the default behavior (replace everything, like opening the file in PyMOL) and the condition for the alternative (merge=True to get two saved scenes side by side). It gives clear context for choosing the merge flag but never names a sibling tool as an alternative for related tasks.

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