Strands Agents MCP Server

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

With no annotations present, the description carries the full burden and largely meets it: it discloses the URL restriction to https://strandsagents.com/, the empty-uri catalog fallback, the small-document bypass that silently ignores the section argument, and the error surface for unsupported URLs, failed fetches, and unknown section IDs. What it does not cover is whether responses are cached, rate-limited, or how large a section payload can get, which matters for an agent planning token budget.

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 document is long but aggressively front-loaded and scannable: mode enumeration first, workflow second, then Args and Returns blocks. The main redundancy is the Returns section, which restates the response shape that an output schema already defines; trimming that would tighten the definition without losing selection-relevant information.

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 two-mode fetch tool with zero annotation coverage and zero schema parameter documentation, the description supplies everything an agent needs: mode selection logic, URL scope constraint, the small-document edge case, the empty-uri catalog path, and the error taxonomy. The presence of an output schema makes the enumerated return fields partly redundant but not harmful, and no decision-relevant behavior 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 0%, so the description must supply all meaning, and it does: uri is defined as a URL constrained to a specific domain with a documented empty-string sentinel behavior ('returns a catalog of all available document URLs with titles'), and section is defined as an ID sourced from the TOC with example formats ('3' or '3.2') and the explicit default of omitting it. Both parameters, including their non-obvious defaults, are fully disambiguated beyond the bare schema types.

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 specific verb and resource ('Read documentation pages') modified by a distinctive mechanism ('smart sectioning for token efficiency'), then enumerates the two operating modes with concrete return shapes for each. It is immediately distinguishable from the sibling search_docs, which is explicitly positioned as the discovery step upstream of this fetch step.

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?

It spells out exactly when each mode fires (omit section vs. provide section), names the boundary condition that overrides both (~8KB documents return full content regardless of mode), and provides a numbered three-step workflow that routes the agent between search_docs and two successive calls to this tool. Nothing about selection is left to inference.

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

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

With no annotations provided, the description carries the full behavioral burden and does substantial work: it discloses the lazy-hydration model (top results fetched on demand), the dual title/body ranking behavior, and the graceful-degradation path where a failed fetch falls back to the title as the snippet. It does not discuss rate limits or fetch failures beyond that fallback, but the important non-obvious behaviors are covered.

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?

Front-loaded core sentence, then ranking behavior, then the handoff to fetch_doc, then Args/Returns blocks — a logical order an agent can scan. The Returns block is somewhat verbose relative to its value since an output schema already exists, but nothing is padding.

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 two-parameter search tool with a sibling and an output schema, this is close to complete: it explains scoring semantics (unbounded TF-IDF, comparable only within a result set, not a probability) and the empty-result case. The Returns enumeration largely restates the output schema, which is the only redundant element.

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 0%, so the description must compensate and largely does: `query` is illustrated with three distinct natural-language/keyword phrasings, and `k` is defined as the maximum number of results with its default of 5. The remaining gap is minor — no guidance on sensible `k` ranges or query length.

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 ("Search the curated documentation catalog") and immediately scopes what the catalog holds — user guides, API reference pages, examples. It also distinguishes itself from the sibling by explicitly delegating page reading to fetch_doc, so an agent can pick between the two without opening a schema.

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 concrete guidance on both directions: use search_docs with title-like keywords ("bedrock model", "MCP tools") or body terms, then "Call fetch_doc with a result URL to read the page or one of its sections." It lacks an explicit when-not case (e.g., when a URL is already known, skip straight to fetch_doc), which keeps it just short of a 5.

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