db_compact

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

The description goes well beyond the annotations by disclosing the exclusive VACUUM lock, the full-file copy cost, the transient FTS mis-mapping risk during the vacuum→rebuild gap, and the soft-fail retry behavior. This gives an agent the operational context needed to decide when and how to invoke this mutating but non-destructive 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?

Three sentences: the first states the operation; the second gives operational warnings; the third covers failure behavior. The key caution is front-loaded before the timeout/error implications. Every sentence adds value without 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 parameterless tool with annotations and an output schema, the description covers the operation, performance cost, locking requirement, correctness hazard, and failure semantics. Nothing important is missing for an agent to safely select and invoke this tool.

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?

There are zero parameters, so the schema already fully describes the input surface. The description correctly spends no space on parameter details. Baseline 4 is appropriate for a parameterless tool.

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 opens with a clear verb and resource: 'Shrink the DB file: VACUUM + mandatory dialog_fts rebuild.' It states exactly what the tool does and differentiates it from maintenance siblings like db_deduplicate_embeddings or forget by identifying the specific compaction operation.

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?

The description gives explicit when-to-use guidance: 'Run in a quiet window' due to the exclusive lock and whole-file copy. It explains the cost profile and failure mode ('Fails soft with a retry hint when the DB is busy'). It does not name alternatives, but no alternative is clearly relevant for this maintenance operation.

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