Narya Sync

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

With no annotations, the description carries the full burden and does notably well: it discloses that commands are retracted from the first changed one onward, that the file is replayed up to `line`, that unchanged commands and imports are preserved, and that passing an earlier `line` moves the session backwards. It omits error/permission behavior and says nothing about `timeout`.

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?

Front-loaded with the core action and then the mechanics; every clause carries operational meaning. The sentences are dense and jargon-laden (Narya `undo`), which costs a little readability but not enough to call it bloated.

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?

An output schema exists, so return values need no prose, and the mutation semantics are covered. What is missing is the undocumented `timeout` parameter and any indication of failure modes, which for a state-altering replay tool is a real gap.

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. It explains `line` (default = whole file, earlier values move the session backwards) well, and `session_id` is inferable from context, but `timeout` is never mentioned, leaving one of three parameters wholly undocumented.

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 names a specific verb and resource ('Re-read the session's file after edits'), then details the retract/replay mechanics and the default scope of `line`. It is clearly distinguishable from a plain checker like narya_check_file, though it never names a sibling to route against.

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?

'After edits' implies the trigger condition, and the default (`line` defaults to the whole file) is called out, which is useful. However there is no explicit when-not guidance and no comparison to adjacent siblings such as narya_check_file or narya_try.

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