List the open fronts

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuine behavioral detail beyond that: the sort order (blockers first, then most-blocking, then newest), the returned fields (alias, kind, state, title, ancestors), and the handoff to vivac_why for more. It doesn't mention output size or pagination behavior, keeping it short of a 5.

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-loaded with the core purpose, and each subsequent clause adds real information (selection rule, ordering, return shape, routing). The ordering clause is dense and slightly cryptic ('holding up the most tree'), but nothing is padding.

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 must carry the return value, and it does: alias, kind, state, title and the ancestor aliases, plus a pointer to vivac_why. Combined with annotations covering safety and zero parameters, an agent has everything needed to call and interpret this tool.

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?

The tool takes zero parameters, so the baseline is 4 and there is no parameter meaning to add. The description correctly avoids implying any filters or options.

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+resource ('List what is still unfinished in this project') and goes further by defining the exact selection rule: nodes with nothing open under them. It then distinguishes itself from siblings by naming vivac_brief and vivac_find, so an agent can route correctly without reading other schemas.

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?

Explicitly states its purpose ('Use it to answer what is left or what is waiting') and names the alternatives with the condition that selects them: vivac_brief for session state, vivac_find for word-based lookup. When-to-use and when-to-use-something-else are both covered.

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