align_files

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

With no annotations, the description carries the full burden and does well: it discloses batching (one StarAlignment execution per batch, max 20), that files are written to output_dir, that matrix_only's temp folder under scratch is deleted afterwards, and that it runs without geometry confirmation dialogs. It stops short of stating required permissions or error handling, but side effects and write locations are covered.

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-loads the core purpose before the mode and directory details. It is dense and somewhat run-on toward the end (matrix_only and result-format clauses are long), but every sentence carries distinct operational information rather than filler.

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 9-parameter mutation tool with no annotations and no output schema, it covers the essentials: where outputs land, the matrix_only deletion behavior, and what the per-target result contains (StarAlignment outputData values). Minor gaps remain around permissions and failure modes.

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 the baseline is 3, but the description adds real meaning beyond the schema: output_dir must lie inside <workspace>/output or the state folder, registered names follow <name><output_postfix>.xisf, and batch_size caps StarAlignment executions rather than just being a number.

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 and resource: 'Register image files onto a reference image file with StarAlignment, file to file (no views are opened).' The 'file to file / no views are opened' phrasing implicitly distinguishes it from view-based siblings like align_to_reference, so an agent can route correctly.

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 explains the matrix_only alternative mode and output_dir placement rules, which helps mode selection. However it never states when to pick align_files over siblings such as align_to_reference or reproject_to_reference, so cross-tool selection is left to inference.

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