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

With no annotations, the description carries the full burden, and it does disclose the key dependency: a prior compile and the existence of output.synctex.gz. However, it says nothing about failure behavior when the file is missing, coordinate validity, or whether it is a pure read. Useful precondition context, but not rich behavioral disclosure.

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?

Three short sentences with the core purpose front-loaded, then usage, then prerequisite. No filler and every sentence contributes distinct information.

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 not be explained. Purpose, direction, and the compile prerequisite are covered; the only real gap is the undocumented coordinate parameters, which keeps it short of fully 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% across 5 parameters (project_id, page, x, y, pdf_filename), yet the description gives no per-parameter meaning. It never clarifies that x/y are PDF point coordinates, that page is a page index, or what pdf_filename (default output.pdf) selects, so the low-coverage gap is not compensated.

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?

States a specific verb ('Resolve'), resource ('PDF coordinates to source file and line'), and mechanism ('via SyncTeX'), plus an explicit direction arrow '(PDF → source)'. This direction marker cleanly distinguishes it from the sibling synctex_forward without needing to open either schema.

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 when to use it ('Use after a compile to map a click position back to the .tex line') and states the precondition ('Requires a prior compile (needs output.synctex.gz)'). It does not name synctex_forward as the inverse alternative for the opposite direction, but the 'PDF → source' framing implies it.

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