session_read

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It clearly indicates this is a read operation (not destructive) and specifies what content is retrieved (visible screen contents). However, it doesn't mention potential limitations like read permissions, rate limits, or what happens with invalid session IDs, leaving some behavioral aspects unclear.

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 perfectly front-loaded with the core purpose in the first sentence, followed by a cleanly formatted parameter section. Every sentence earns its place - the first establishes purpose, the parameter explanations provide essential usage context without 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?

Given the tool has an output schema (which handles return values), 2 parameters with full semantic coverage in the description, and no annotations, the description is quite complete. It could be slightly improved by mentioning potential error conditions or clarifying the 'visible screen' scope, but it provides solid foundation for tool usage.

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?

With 0% schema description coverage, the description fully compensates by providing clear semantic explanations for both parameters: session_id ('Target session ID. Omit for the active session.') and lines ('Number of lines to return from the bottom. Omit for all visible lines.'). This adds crucial meaning beyond 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?

The description clearly states the specific action ('Read the visible screen contents') and target resource ('of an iTerm2 session'), distinguishing it from sibling tools like session_list (which lists sessions) or session_send (which sends input). It uses precise terminology that differentiates its function.

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 implies usage by specifying what the tool reads (visible screen contents), but doesn't explicitly state when to use it versus alternatives like session_get_variable or session_list. It provides some context through parameter descriptions but lacks explicit guidance on tool selection scenarios.

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