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

With no annotations supplied, the description carries the full burden; it does disclose read-only behavior ('Side effects: None') and the return shape ('JSON array with epistemic status and Pi Pointers'), which is genuinely useful. It says nothing about ordering/ranking, truncation behavior when limit is hit, or empty results, leaving key behavioral questions unanswered.

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?

Two short sentences, front-loaded with the scope marker and the core action, with return and side-effect notes after. Nothing is redundant, though the '[PUBLIC READ]' prefix partially duplicates the later 'read-only' statement.

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-required search tool with no output schema, the description covers action, inputs, return contents and safety profile adequately. Gaps remain around result ordering, limit exhaustion, and how it differs from vault_read, but nothing required to invoke it correctly 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 coverage is 75%, so the schema already documents all four parameters well. The description only echoes two of them (keywords → query, tags → tag) and adds no detail on limit or category, nor on how query and tag interact. Baseline 3 applies since the schema does the heavy lifting.

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 states a specific verb and resource ('Search the knowledge vault') plus what is searched (cells, facts, invariants) and by what means (keywords or tags). It is clearly a search rather than a direct read, which implicitly separates it from vault_read, but no sibling is named explicitly.

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?

Usage is only implied: the word 'Search' suggests retrieval by keyword/tag as opposed to fetching a known item via vault_read, but there is no explicit when-to-use or when-not-to-use statement. An agent must infer its place among the ~19 vault/session/map siblings.

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