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

Adds context the readOnlyHint annotation cannot: it temporarily mutates :SYSTem:PICture:FORMat and always restores the original, documents a hard failure mode (truncation at 144,800 bytes over raw TCP), and gives an expected latency. The name/schema give no hint of these traits, though the disclosure could state whether the refusal surfaces as an error or a text reply.

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 sentences, each carrying distinct load — outcome, gating constraint, side effect and duration — with the primary result front-loaded. No filler or restatement of the title.

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 one-parameter capture tool with a readOnlyHint annotation this is nearly complete: output type, transport requirement, side-effect restoration, and timing are all covered. A brief note on whether a failed capture returns an error versus an explanatory string would close the remaining 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 100% and the single parameter is fully described there (name from list_instruments, default behavior). The description adds no further meaning about the instrument parameter, so the baseline 3 applies.

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 ('Capture the analyzer's screen') plus the return format ('PNG image'), which no sibling tool in the catalog does. An agent can select it without opening the 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?

Explains the transport prerequisite that gates successful use (VXI-11 required, raw TCP refuses with instructions) and the ~3 second cost, which shapes when to call it. It offers no explicit comparison to alternative tools, so guidance is implied rather than comparative.

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