tool_read_element

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

With no annotations provided, the description carries the burden. It discloses that the tool is read-only and explains that stale refs are reported rather than guessed. It doesn't detail error handling or output format, but these are likely covered by the output schema. The key behavioral trait of staleness reporting is clearly communicated.

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 two sentences, with the core action and source stated first, followed by the usage scenario and staleness behavior. Every word earns its place; there is no redundancy or 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 single-parameter read tool with an output schema (even though not shown), the description covers purpose, usage, and the key behavioral nuance of staleness. The agent has enough to decide when to call it and what to expect, and the output schema presumably covers return values.

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. It explains that 'ref' is a reference returned by element_at_point and clarifies that it can become stale. This adds meaning beyond the bare 'string' type, giving the agent enough context to use the parameter correctly.

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 verb ('re-read') and resource ('UI element'), and clarifies the ref comes from element_at_point. It distinguishes itself by focusing on re-reading a specific element rather than performing actions on it, making its purpose clear and unique among siblings.

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?

It provides explicit guidance on when to use it ('Use this to check whether an element is still there before acting on it') and explains the stale ref scenario. It doesn't name alternative tools explicitly, but the context implies its role in the verification step. A slight gap is the lack of explicit 'when not to use' guidance.

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