Scan proto functions

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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds genuinely useful context: cost=high, requires an active client, and output is bounded-candidates. The failure-path guidance (consult tool-schema) is a nice extra, though return shape detail is thin.

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 purpose before the metadata and is compact. Some redundancy exists ('idempotency=read-only' and 'Safety: read-only' both duplicate the readOnlyHint annotation), but the structured phrasing keeps it scannable.

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 3-optional-param read-only scan with no output schema, the description covers prerequisites, cost, and the nature of the output (bounded-candidates). It is largely complete, missing only an explicit distinction from sibling proto-scanning tools.

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%, so the schema already documents query, limit, and threadContext with defaults and constraints. The description only restates the signature with types and adds no syntax or format detail beyond the schema, so 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 (scan) and resource (proto functions) and names the underlying mechanism (debug.getprotos over matched functions), so the agent knows what it does. It does not distinguish itself from close siblings like get-function-protos or get-closure-protos, so it falls short of the top score.

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?

Provides contextual signals ('Phase: observe', 'Requires: active-client', 'cost=high') that imply when it fits, and the failure note routes to tool-schema. However, it never states when to choose this over sibling proto tools, leaving the alternative selection to inference.

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