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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so safety and repeatability are covered. The description adds useful scope information by naming the returned sections, but says nothing about whether the response is bulky, whether tracking plans are summaries or full versions, or about failure modes for an invalid source_id.

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 compact sentence that front-loads the verb and the payload enumeration; nothing is redundant. It is slightly terse to the point of being a fragment, but no words are wasted.

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?

With no output schema, the description is the only place the return contents are conveyed — and it does name them, which is its main contribution. However, for a tool with two required params and a partly undocumented workspace_id, it leaves gaps an agent must resolve by trial.

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 only 50%: source_id is documented in the schema ('Source ID from list_sources output') while workspace_id carries no description anywhere. The description adds no parameter meaning at all, so it fails to compensate for the undocumented required parameter.

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?

Uses a specific verb and resource ('Get ... source details') and enumerates the payload shape: configuration, tracking plans, connected destinations. That distinguishes it from list_sources and metric-oriented siblings, though it never names the closest alternative (get_source_tracking_plans_and_versions) to resolve the apparent overlap over tracking-plan content.

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?

Retrieval-for-a-known-ID usage is implied by 'Get ... details' and the required source_id, but there is no explicit when-to-use or when-not guidance against siblings such as get_source_definitions or get_source_tracking_plans_and_versions. The agent has to infer the routing itself.

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