aimasteracc/mycelium/inheritance

inheritance — class/trait/interface relationships

This Skill bundles the 8 Extends and Implements edge tools. Reach for it when the question involves type hierarchies — class extension chains, interface implementations, trait dispatch resolution.

Language note: Rust has no class inheritance, but trait impl X for Y produces Implements edges. C++/C#/Java/Python/TypeScript projects exercise both edge kinds heavily.

When to invoke this Skill

Use when:

• The user asks "who extends/implements X", "what does X extend", "what's the parent class of X".
• Tracking down where polymorphism resolves at runtime — "which concrete Repository impls exist".
• Refactoring an abstract base — need the full set of subclasses or implementors.

Do NOT use when:

• The relationship is Calls (use call-graph) or Imports (use import-graph).
• The user wants multi-edge-kind reachability (use reachability).

Quick examples

Capabilities under this umbrella

get_extends — direct parent class(es)

mcp__mycelium__get_extends({ "path": "src/auth/oauth.py>OAuth2Session" })
→ { "extends": ["src/auth/base.py>BaseSession"], "count": 1 }

extends_tree — recursive extends chain

Walks up: this class → its parent → grandparent → ... up to max_depth.

mcp__mycelium__extends_tree({ "path": "src/auth/oauth.py>OAuth2Session", "max_depth": 5 })

subclasses_tree — recursive subclass tree

Walks down: this class → its subclasses → their subclasses. The "who extends this" tree.

mcp__mycelium__subclasses_tree({ "path": "src/auth/base.py>BaseSession", "max_depth": 5 })

find_extends_path — concrete-to-abstract chain

"Show me the inheritance chain from OAuth2Session to BaseSession":

mcp__mycelium__find_extends_path({
  "from": "src/auth/oauth.py>OAuth2Session",
  "to": "src/auth/base.py>BaseSession"
})
→ { "path": ["src/auth/oauth.py>OAuth2Session", "src/auth/jwt.py>JwtSession", "src/auth/base.py>BaseSession"], "length": 3 }

Returns { "path": null } if the symbols are not in the same chain.

get_implements — what interfaces/traits does X implement

mcp__mycelium__get_implements({ "path": "src/db/postgres.rs>PostgresUserRepo" })
→ { "implements": ["src/repo.rs>UserRepository", "src/repo.rs>Healthcheckable"], "count": 2 }

implements_tree — recursive implements chain

For interfaces/traits that extend other interfaces/traits — Rust's "supertrait" pattern, Java's interface A extends B.

implementors_tree — recursive "who implements this"

The trait/interface analog of subclasses_tree. Returns every concrete type that implements the given trait/interface, walking down through trait inheritance.

find_implements_path — concrete-to-interface chain

Counterpart of find_extends_path for the Implements edge.

Common chains

• "Where does this trait/interface get dispatched?" → implementors_tree.
• "Which subclasses inherit X?" → subclasses_tree.
• "What does X bring along when extended?" → extends_tree (parents' contracts).
• "Is X a subclass / implementor of Y?" → find_extends_path / find_implements_path.

Equivalent CLI

mycelium subclasses-tree "src/auth/base.py>BaseSession" --max-depth 5 --format=json
mycelium find-implements-path --from "src/db/postgres.rs>PostgresUserRepo" --to "src/repo.rs>UserRepository"
mycelium implementors-tree "src/repo.rs>UserRepository" --max-depth 3

Parity contract

Per RFC-0090. tests/parity.test.json uses a small Python fixture with a 3-class extends chain plus a trait/interface scenario.

Cross-references

• Related Skill: call-graph — for method-level dispatch (which impl actually runs).
• Related Skill: reachability — for cross-edge-kind navigation.
• Related Skill: basic-queries — to find the class/trait symbol first.