Get the best common ancestor of two Bitbucket branches, tags, or commit hashes to check ancestry by comparing the returned hash with a resolved commit.
Get Bitbucket's best common ancestor of two branches, tags or hashes.
Useful for ancestry checks: compare the returned hash with a resolved commit.
Bitbucket returns one best ancestor, even if the graph has several.
| Name | Required | Description | Default |
|---|---|---|---|
| base | Yes | ||
| head | Yes | ||
| repo_slug | Yes |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It valuably discloses that Bitbucket returns a single best ancestor even when several exist, but it omits permission requirements, error behavior when no common ancestor exists, and does not explicitly frame this as a safe read operation.
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?
Three short sentences with the core purpose front-loaded and no wasted text. The final sentence adds a non-obvious behavioral nuance and earns its place.
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?
For a simple three-parameter read tool with no output schema, the description covers purpose, usage, and the key return behavior. It could still say more about repo_slug and the no-common-ancestor case, but it is largely 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 coverage is 0%, so the description must compensate. It does partially by explaining that base/head accept branches, tags, or hashes, but repo_slug is left unexplained and no format details or examples are provided for any 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?
States a specific verb and resource: returns Bitbucket's best common ancestor of two refs. The concept of a merge-base is distinct from sibling tools like compare_commits or get_commit, so an agent can identify it without opening the schema.
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?
Gives a clear usage scenario ('Useful for ancestry checks: compare the returned hash with a resolved commit') but does not name alternatives or say when not to use it. That is clear context without exclusions, matching a 4.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.