sources_of

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

With no annotations, the description carries the full burden of behavioral disclosure. It communicates the reverse-traversal direction, but it does not explain what 'path_shape' means, how results are returned, whether traversal is bounded, or what side effects or costs may exist.

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 short and front-loads the core idea, which is good. However, the trailing 'path_shape' fragment earns no place and adds ambiguity rather than useful context, so the efficiency is undermined.

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?

There is no output schema, no annotations, and only one of three parameters is meaningfully documented. The description conveys the input and kind of traversal, but it does not tell the agent what a result page or path shape looks like, so the agent has limited ability to interpret the response.

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 only 33%, so the description must compensate. It adds meaning to 'sink' by defining it as the target of the value flow, but 'limit' gets no explanation beyond its schema default, and 'format' only gets a schema-level enum description. This is not enough for a low-coverage schema.

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 reverse direction ('Reverse value-flow cone') and the core question ('which values can feed this sink'), making the tool's purpose clear: take a sink and identify upstream source values. The use of 'sink' and 'value-flow' distinguishes it from sibling call-graph or forward-flow tools, though the trailing 'path_shape' is unexplained jargon.

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 implies when to use it: when you have a sink and want the values that can reach it. It does not, however, name any alternatives or mention when not to use this tool versus the many related graph/value-flow siblings.

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