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

Annotations only declare readOnlyHint/openWorldHint, and no output schema exists, so the description's disclosure of the return shape (errors with line and column, or 'ok' with lane, message and payload count) is genuinely load-bearing context. It stops short of auth or rate-limit notes, but the return-behavior disclosure is real added value.

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 first two sentences are well front-loaded and earn their place. The remaining two-thirds is a syntax catalog for Volley source that helps author parameters but is bulky and likely duplicated across sibling tools, diluting selection-relevant 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?

For a read-only, two-parameter tool with no output schema, the description covers what is returned in both the error and success cases, which is the main gap structured data would otherwise leave. Only the missing sibling differentiation keeps it from being 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 coverage is 100%, so both id and source are already documented in the schema, and the description does not add id-vs-source selection rules. The syntax reference implicitly describes valid 'source' content but is not tied to the parameter, so the 3 baseline is appropriate.

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 first sentence gives a specific verb and resource: 'List parse errors and warnings for a Volley diagram, each with line and column.' It also states the negative case ('Returns ok ... when there are none'). However, it never distinguishes itself from the similarly-named verify_diagram sibling, so an agent may not know which validation tool to pick.

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?

There is no when-to-use guidance and no alternative named, even though verify_diagram and describe_diagram are obvious candidates for confusion. The description only implies usage by listing what it returns, leaving the selection decision to inference.

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