Compact graph digest (token-cheap)

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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description adds valuable context beyond that: it reveals the tool uses getNetworkTopology and getNetworkErrors, performs 'no new bridge work,' and returns an approxTokens count. This gives the agent a clear mental model of cost and side effects.

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 three sentences, front-loaded with the read-only flag, and every sentence carries unique information: what it does, what it returns, and how it compares to alternatives. There is no wasted text.

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?

An output schema exists, so the return shape is already documented, and the description covers the tool's purpose, underlying mechanism, and relative cost vs. siblings. For a read-only planning digest, this is complete enough for an agent to select and invoke it correctly.

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 all six parameters already have robust descriptions. The tool description mentions max_tokens as a default budget but does not add new per-parameter semantics beyond what the schema already provides, so the baseline score of 3 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 description opens with a specific verb-resource pairing: 'compress a TD subtree into a structured digest,' which clearly states the tool's function. It further differentiates from siblings by explicitly naming get_td_topology and snapshot_td_graph as costlier alternatives, so purpose and differentiation are both strong.

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 gives a clear use case ('for planning turns') and explicitly names alternatives ('Cheaper than get_td_topology / snapshot_td_graph'), which tells the agent when this is preferable. However, it does not explicitly state when not to use it, so it falls just short of a full 5.

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