session_tail

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

With no annotations, the description carries the transparency burden. It discloses the key non-blocking behavior, the read-only nature implied by 'peek', and the return shape {name, state, output}. It does not detail error handling or edge cases, but for a simple read operation it is adequately transparent.

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, only 26 words, and the primary purpose is front-loaded. Every word earns its place with no fluff 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?

For a simple read tool with no output schema, the description covers the essential context: when to use, the non-blocking nature, and the return structure. It does not elaborate on parameter details or edge cases, but given the simplicity and sibling context, it is sufficiently complete.

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 0%, so the description must compensate for parameter explanations. It implicitly references the 'lines' parameter via '*lines*' but does not explicitly explain its meaning or the 'name' parameter beyond hinting it identifies a pane. The schema already provides types and defaults, but additional explicit parameter context would be better.

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 tool's function with a specific verb ('peek'), a specific resource ('pane output'), and a precise scope ('last *lines*'). It also explicitly contrasts with blocking operations, making it distinct from sibling tools like session_wait.

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 provides clear usage context: 'use this to check on a long-running task instead of assuming it is stuck.' It does not name alternative tools explicitly, but the advice to avoid blocking implies a clear scenario and distinguishes it from blocking wait/status operations.

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