session_fill

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

No annotations are provided, so the description carries full responsibility for behavioral disclosure. It reveals the supported target kinds and rich text editors, but does not disclose whether the fill overwrites existing content, fires input events, requires visibility, or what happens if the selector/ref is missing. These are material behaviors for a form-filling action.

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 sentences with no filler. The first sentence states the action and target, and the second adds relevant scope (rich text editors). Nothing is redundant or bloated.

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 four parameters, no annotations, and no output schema, the description leaves important gaps: parameter semantics for selector and value, behavioral expectations (overwrite vs append, event triggering), and when to choose this over the similar 'session_type' sibling. It is too sparse to fully guide an agent on correct invocation.

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 only 25%, with only 'ref' described. The description does not compensate: 'with a value' adds no more meaning than the 'value' parameter name already implies, and it says nothing about how to construct 'selector' or when to use 'tabId'. The useful 'ref' semantics are already in the schema, so the description's contribution is minimal.

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?

The description states a specific action ('Fill') and resource ('form field (input, textarea, or contenteditable)'), plus supported rich text editors. This makes the core purpose clear. However, it does not explicitly distinguish this from the sibling 'session_type', which could perform similar actions in some contexts.

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?

No explicit guidance on when to use this tool versus alternatives like 'session_type' or 'session_click'. The mention of ProseMirror, Lexical, Slate and other rich text editors implies a use case, but it stops short of stating 'use this when interacting with rich text editors' or mentioning that 'session_type' is preferred for normal inputs.

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