memkernel_diff_branches

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

With no annotations, the description carries the full burden, and it does disclose meaningful behavior: it computes a merge base and surfaces conflicts between sides, which tells the agent this is a non-mutating analytical operation. However, it says nothing about permissions, cost, or whether it writes anything (e.g., a diff artifact), leaving gaps for a no-annotation tool.

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 front-loaded sentence that states the action first and then the outputs, with no filler. Well sized for the operation.

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?

Because an output schema exists, the description need not explain return values, and it already previews the key result categories. For a two-parameter read tool that is close to adequate, but the missing parameter meaning and total absence of usage/behavioral context (no annotations to lean on) leave it only minimally complete.

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 0%, so the description must compensate for the two undocumented parameters, and it largely does not. 'Two branches' plus 'each side' only loosely implies branch_a and branch_b are the compared endpoints; nothing clarifies whether these are names, IDs, or references.

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 gives a specific verb+resource ('Compare two branches') and even enumerates the comparison surface: merge base, events ahead on each side, conflicting decisions and facts. That is far more informative than the name alone and implicitly separates it from list_branches/history. It stops short of naming a sibling to differentiate against, so a 4 rather than 5.

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?

There is no when-to-use guidance, no prerequisites, and no reference to alternatives such as history or query_state. The comparison intent is implied by the verb, but an agent gets no help deciding when a diff is warranted versus another inspection tool.

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