Sync .faf to CLAUDE.md

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

Annotations already declare idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds real behavioral context beyond that: each target file preserves all lines outside faf's block, and failures are returned per-file with a reason plus isError. It does not say whether concurrent writes are safe, but the merge semantics are a meaningful addition.

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?

The purpose is front-loaded, but the text is one long run-on with redundant jargon — "faf-cli's render and injector" and "with faf-cli's writers" say the same thing twice and cost the reader without adding information. It is functional but not tight.

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?

An output schema exists, so return-value documentation is not strictly required, yet the description usefully frames the write results and failure reporting. With 6 optional params all documented in the schema, and file-preservation semantics stated, an agent has enough to invoke it correctly; only the sibling distinction is missing.

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 the baseline is 3. The description restates the flag-to-file mapping (agents, cursor, gemini, copilot, all) that the schema already documents, adding no syntax, precedence (e.g. all vs a single flag), or default behavior beyond it.

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 — writing project.faf into CLAUDE.md as a faf-managed block, optionally into four other files. It is clear what the tool does, but it never distinguishes itself from the sibling faf_tri_sync, which is the nearest potential overlap, so an agent cannot rule that one out from the text alone.

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?

"Use it after editing project.faf" gives a concrete trigger condition that tells the agent when this tool is appropriate. It provides no when-not guidance and does not name alternatives among the 13 siblings, so it stops short of full routing guidance but is more than implied usage.

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