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

Annotations already declare destructiveHint=true, readOnlyHint=false, and idempotentHint=false, so the safety profile is covered. The description adds real value beyond them by disclosing the side effect that 'Write actions (create, update, delete) each produce a commit' and that with_metadata is required to obtain the SHA used by update/delete. It omits permissions/auth requirements and rate-limit behavior.

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 dense sentences, front-loaded with the overall capability, then the write side effect, then action-routing rules. No filler or repetition.

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 16-parameter, no-output-schema tool, the description covers action routing and the key write side effect, and the schema fully documents parameters. It does not mention pagination (page/limit for tree), return shape for read/list, or auth needs, which would be needed for a 5.

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 baseline is 3. The description goes beyond the schema by explaining the cross-parameter dependency chain: with_metadata=true on read yields the SHA that update/delete require, and it groups ref vs branch_name vs sha by action. This is useful semantics the schema only states piecemeal.

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 set (read/list/write) and resource (files in a repository), and enumerates the six actions so the agent knows the tool's full scope without opening the schema. It is clearly distinguishable from siblings like commits, branches, and repos, which handle different resources.

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 explicit action-selection guidance: 'read' for content, 'list' for one directory level, 'tree' for a recursive listing, and notes with_metadata=true when the SHA is needed. It does not state when *not* to use this tool versus a sibling (e.g. commits for history), so it stops 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.