plot_grid_ionising_luminosity

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

With no annotations, the description carries the full burden. It discloses that the tool writes a file (via 'written path') and returns a mapping with ok/error, so the main side effect and possible failure are clear. It does not explicitly state whether it modifies the grid, but the nature of plotting implies non-destructive behavior, which is acceptable.

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?

The description is compact and front-loaded with the core action, then adds the diagnostic context, followed by parameter and return details. Every sentence serves a purpose; there is no fluff or repetition. It is well-structured and easy to scan.

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?

The description covers the purpose, parameters, return format, and error state. An output schema exists, but the description still explains the return mapping clearly, making the tool fully callable without further investigation. For a two-parameter plotting tool, nothing essential is missing.

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 does so well: it explains grid_name as a grid name with or without a file suffix, and ion as either HI or HeII, effectively documenting both parameters with meaningful contexts beyond the raw type. No information is left to guesswork.

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 states a specific action (plot) on a specific resource (grid's specific ionising luminosity) and explains its diagnostic role. It clearly distinguishes from siblings like plot_grid_spectra and plot_grid_lines by naming the exact quantity plotted, so an agent can differentiate without opening schemas.

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?

It says 'This is the standard diagnostic for whether a grid covers the ionising output a study needs,' giving clear guidance on when to use it. It does not explicitly mention alternatives or exclusions, but the context makes it obvious that for spectra or lines you would use the sibling tools, so it is still useful.

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