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

With no annotations provided, the description carries the full behavioral burden. It conveys that this is a diagnostic/read-only style operation and discloses the result shape (path/line/severity/error message), which is especially valuable since there is no output schema. It does not mention error handling or side-effect caveats, but it is transparent about what the tool does and returns.

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?

A single sentence with no filler. It front-loads the main action, then compactly specifies target file types and return fields, so every clause earns its place.

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 tool with no output schema and no annotations, the description covers the essential invocation details: what input is expected, what file types are supported, and what the tool returns. It lacks an explicit comparison to check_project, but the description's single-file scope makes the intended use clear.

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?

The input schema already fully documents the single path parameter, so the baseline is 3. The description adds meaning beyond the schema by specifying which file types are valid targets, which enriches an otherwise generic 'path' string.

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 ('Run Spyglass diagnostics on one Minecraft datapack file') and lists supported file types. The 'one ... file' framing clearly distinguishes it from the sibling project-level check_project.

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 clearly scopes the tool to a single file rather than a whole project, giving an agent the key context for when to invoke it. It does not explicitly name check_project as the alternative or state exclusions, so it falls just short of a 5.

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

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

With no annotations, the description carries full behavioral burden. It only discloses that the first run may download a cache and take time. It does not state whether the tool is read-only, modifies files, requires specific permissions, or what side effects result. This is a significant gap for an agent deciding whether to invoke it.

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 two sentences with zero waste. The main purpose is front-loaded, followed by specific parameter guidance and a behavioral warning. It is efficient 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?

It covers what, how, and a caveat about first-run performance, but lacks information about the output format or what the agent should expect in the response (e.g., a report, exit code). For a tool with no annotations and no output schema, this is a notable omission.

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?

The schema description for 'root' has 100% coverage and is clear ('Datapack or workspace root. Defaults to...'), and the tool description adds extra context ('folder with pack.mcmeta or a parent folder'). This fully clarifies what to pass and its optionality.

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 verb ('Run Spyglass') on a specific resource ('every .mcfunction, pack JSON, .mcmeta, .snbt, and .mcdoc file') with a scope ('under a datapack workspace'). This clearly distinguishes it from a sibling like check_file, which focuses on a single file. The purpose is unambiguous.

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 provides clear usage context: it tells the agent what to pass ('the pack root... or a parent folder') and implies it is for whole-project checking rather than single files. However, it does not explicitly state when NOT to use it or name the sibling alternative, leaving that to inference from the name.

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