CEL See

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

Despite no annotations, the description provides rich behavioral details: default timeout for wait_for_element (10s), requirement for wait_for_idle (2 consecutive stable polls), 18 event types for watch, CDP limits (50 text_blocks, etc.), and conflict note about cel_perceive. This goes far beyond simple annotations.

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 well-organized with clear sections (Screen Context, Element Inspection, Browser, Observation Recall, Waiting & Watching, Limits). Each sentence adds value, providing necessary detail without redundancy. Front-loaded with purpose.

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?

Given no output schema, the description lists categories of returned data but does not fully specify output structure. However, it covers key aspects like limits and sub-function behaviors. It feels complete for a read tool, though a more structured output spec would be even better.

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?

There are zero parameters in the input schema, and the description compensates by thoroughly explaining all the tool's sub-functions (Screen Context, Element Inspection, etc.). According to guidelines, 0 params = baseline 4; this description exceeds that with detailed breakdown of capabilities.

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?

Description explicitly states 'Read and observe the current screen state' and lists many capabilities. It distinguishes from siblings by saying 'Always use this BEFORE acting', making clear this is the observation tool while cel_act is for actions and cel_perceive for perception.

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?

The description gives clear usage advice: 'Always use this BEFORE acting'. It also notes a limitation (watch unavailable during cel_perceive session). However, it does not explicitly state when not to use or provide direct comparison with cel_perceive.

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