av_session_start

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

With no annotations, the description carries the burden and does well: it discloses auto-monitoring with an ~8s debounce under MCP, that the CLI does not continuously monitor, the need to echo the returned path.checking, and that the tool is fully offline. It stops short of describing what the snapshot records or any failure/abort behavior beyond the editDir mismatch noted in the schema.

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?

Purpose is front-loaded and every clause carries operational weight (monitoring, offline, required path echo). It is somewhat crammed into a few dense sentences, but there is no filler to cut.

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 session-start tool with no annotations and no output schema, the description supplies the behavioral context an agent needs (monitoring semantics, offline mode, required echo of output). Only minor gaps remain around what the snapshot contains or how failures surface.

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 100%, so all four parameters are already documented with descriptions including the worktree warning and the Git-root constraint. The description reinforces that repo must be the workspace absolute path, but adds no format or syntax beyond the schema, matching the baseline-3 rule.

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 opening clause states a concrete action and metaphor (take a 'before' snapshot recording current structure) and the tool name plus sibling reference make the resource clear. It is identifiable as a session-initialization tool distinct from the report/changes siblings, though the purpose statement is interleaved with operational caveats rather than cleanly separated.

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?

Explicitly says to run before editing code, notes the daily-priority alternative (av_guard), and distinguishes MCP-backed auto-monitoring from the CLI path that requires a manual report. When-to-use, when-to-prefer-a-sibling, and the environment-dependent difference are all stated without inference.

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